Advertisements
Feeds:
Posts
Comments

Archive for the ‘Gastroenterology’ Category


Curator: Gail S. Thornton, M.A.

Co-Editor: The VOICES of Patients, Hospital CEOs, HealthCare Providers, Caregivers and Families: Personal Experience with Critical Care and Invasive Medical Procedures

  •  In a national survey, the Fiber Choice® line of chewable prebiotic fiber tablets and gummies, achieved the #1 share of gastroenterologist (GE) recommendations, more than four times greater than that for the nearest branded competitor
  • Fiber Choice contains a well-studied prebiotic fiber that promotes regularity and supports the growth of beneficial microorganisms for general digestive health
  • The convenience, taste and efficacy of Fiber Choice, makes it a GE-endorsed choice toward helping address the “fiber gap” in American diets

 Boca Raton, Fla. – (June 3, 2018) – IM HealthScience® (IMH), innovators of medical foods and dietary supplements, today announced a high-quality and replicated nationwide survey conducted among a representative and projectible sample of U.S. gastroenterologists, which revealed Fiber Choice® as the #1-recommended chewable prebiotic fiber brand.

The results of a ProVoice survey, fielded in May 2018 by IQVIA, showed Fiber Choice as the leader by far. Its share of gastroenterologist endorsements was more than four times greater than that of its nearest branded competitor.

Less than 3 percent of Americans get the recommended minimum amount of fiber, and 97 percent need to increase their fiber intake[1]. Although the recommended daily fiber intake is 25 to 38 grams[2], most Americans only get about half that amount. This “fiber gap” reflects a diet with relatively few high-fiber foods, such as fruits, vegetables, nuts, legumes and whole-grains, and is large enough for the U.S. government to deem it a public health concern for most of the U.S. population.

To help bridge this gap, gastroenterologists recommend fibers including Fiber Choice chewable tablets and gummies. For doctors, it’s a simple, convenient and tasty way to help their patients get the fiber needed for overall good digestive health.

“Dietary fiber is known for keeping our bodies regular,” said Michael Epstein, M.D., FACG, AGAF, a leading gastroenterologist and Chief Medical Advisor of IM HealthScience. “Most importantly, it’s essential that you get enough fiber in your diet. One way to do that is to supplement your daily intake of dietary fiber with natural, prebiotic fiber supplements.”

Inulin, the 100 percent natural prebiotic soluble fiber in Fiber Choice, has been studied extensively and has been shown to support laxation and overall digestive health as well as glycemic control, lowered cholesterol, improved cardiovascular health, weight control and better calcium absorption.

Fiber Choice can be found in the digestive aisle at Walmart, CVS, Target, Rite Aid and many other drug and food retailers.

About ProVoice Survey
ProVoice has the largest sample size of any professional healthcare survey in the U.S., with nearly 60,000 respondents across physicians, nurse practitioners, physician assistants, optometrists, dentists, and hygienists, measuring recommendations across more than 120 over-the-counter categories. Manufacturers use ProVoice for claim substantiation, promotion measurement, and HCP targeting.

IQVIA fielded replicated surveys in April 2018 and May 2018 respectively among U.S. gastroenterologists for IM HealthScience. The ProVoice survey methodology validated the claim at a 95 percent confidence level that “Fiber Choice® is the #1 gastroenterologist-recommended chewable prebiotic fiber supplement.”

About Fiber Choice®

The Fiber Choice® brand of chewables and gummies is made of inulin [pronounced: in-yoo-lin], a natural fiber found in many fruits and vegetables. Inulin works by helping to build healthy, good bacteria in the colon, while keeping food moving through the digestive system. This action has a beneficial and favorable effect in softening stools and improving bowel function.

Research shows that the digestive system does more than digest food; it plays a central role in the immune system. The healthy bacteria that live in the digestive tract promote immune system function, so prebiotic fiber helps nourish the body. Inulin also has secondary benefits, too, of possibly lowering cholesterol, balancing blood chemistry and regulating appetite, which can help reduce calorie intake and play a supporting role in weight management.

The usual adult dosage with Fiber Choice Chewable tablets is two tablets up to three times a day and for Fiber Choice Fiber Gummies is two gummies up to six per day.

About IM HealthScience®

IM HealthScience® (IMH) is the innovator of IBgard and FDgard for the dietary management of Irritable Bowel Syndrome (IBS) and Functional Dyspepsia (FD), respectively. In 2017, IMH added Fiber Choice®, a line of prebiotic fibers, to its product line via an acquisition. The sister subsidiary of IMH, Physician’s Seal®, also provides REMfresh®, a well-known continuous release and absorption melatonin (CRA-melatonin™) supplement for sleep. IMH is a privately held company based in Boca Raton, Florida. It was founded in 2010 by a team of highly experienced pharmaceutical research and development and management executives. The company is dedicated to developing products to address overall health and wellness, including conditions with a high unmet medical need, such as digestive health. The IM HealthScience advantage comes from developing products based on its patented, targeted-delivery technologies called Site Specific Targeting (SST). For more information, visit www.imhealthscience.com to learn about the company, or www.IBgard.com,  www.FDgard.comwww.FiberChoice.com, and www.Remfresh.com.

This information is for educational purposes only and is not meant to be a substitute for the advice of a physician or other health care professional. You should not use this information for diagnosing a health problem or disease. The company will strive to keep information current and consistent but may not be able to do so at any specific time. Generally, the most current information can be found on www.fiberchoice.com. Individual results may vary.

SOURCE/REFERENCES

[1] Greger, Michael, M.D., FACLM. (2015, September 29). Where Do You Get Your Fiber? [Blog post]. Retrieved from https://nutritionfacts.org/2015/09/29/where-do-you-get-your-fiber/

[2] Institute of Medicine. 2005. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Washington, DC: The National Academies Press. https://doi.org/10.17226/10490.

Other related articles published in this Open Access Online Scientific Journal include the following:

2018

Benefits of fiber in diet

https://pharmaceuticalintelligence.com/2018/03/14/benefits-of-fiber-in-diet/

2016

Nutrition & Aging: Dr. Simin Meydani appointed Vice Provost for Research @Tufts University

https://pharmaceuticalintelligence.com/2016/08/01/nutrition-aging-dr-simin-meydani-appointed-vice-provost-for-research-tufts-university/

2015

Advertisements

Read Full Post »


Results of New Clinical Data Presented at Digestive Week (DDW), Symptom Reduction and Rapid Pain Relief of Functional Dyspepsia with FDgard®

Reporter: Gail S. Thornton, MA

 

RESULTS OF NEW CLINICAL DATA PRESENTED AT DIGESTIVE DISEASE WEEK (DDW), A PREMIER GASTROENTEROLOGY MEETING, SHOW UNPRECEDENTED SYMPTOM REDUCTION AND RAPID RELIEF OF FUNCTIONAL DYSPEPSIA (FD – PERSISTENT OR RECURRING INDIGESTION) WITH FDgard®, A NEW PRODUCT FOR THIS CONDITION

 First-ever clinical study highlights an advance in the management of Functional Dyspepsia (FD) with FDgard®, a new, non-prescription medical food specially formulated for the dietary management of FD

  • In FD patients, FDgard® significantly reduced symptoms of FD in as early as 24 hours
  • Data showed FDgard®, as an add-on product, improved FD symptoms in patients already using commonly used, off-label medications prescribed for FD
  • Functional Dyspepsia, known for its symptoms of persistent or recurring indigestion, impacts an estimated 1 in 6 adults in the U.S.
  • This medical advance is important because there are no approved products for FD

 CHICAGO – (May 8, 2017) – Landmark clinical data highlight an advance in the management of Functional Dyspepsia (FD) with FDgard®, the only product available for the dietary management of FD. FDgard® demonstrated unprecedented symptom reduction and rapid relief of FD symptoms in patients in only 24 hours. This data was presented during Digestive Disease Week (DDW), a premier gastroenterology meeting.

FDgard® showed effective symptom reduction and rapid relief of FD symptoms in a sub-group of FD patients with Epigastric Pain Syndrome (EPS, which is epigastric pain or burning) and Postprandial Distress Syndrome (PDS, which is early fullness, pressure and heaviness). Additionally, the study findings showed that FDgard® as an add-on product improved FD symptoms in patients already using commonly used, off-label medications prescribed for FD, such as proton pump inhibitors (PPIs) and histamine receptor 2 antagonists (H2RAs), anticonvulsants, antibiotics, antihistamines, antidepressants, and antacids as rescue medications (permitted no more than three doses per week).

FD is often characterized as persistent or recurring indigestion with no known organic cause and is an area of high unmet medical need. Currently, off-label medications are used to treat FD as there is no U.S. Food and Drug Administration (FDA)-approved pharmaceutical product for the condition.

Data from the landmark, multi-centered, post-marketing, parallel group, U.S-based study, entitled FDREST™ (Functional Dyspepsia Reduction and Evaluation Safety Trial), showed that patients with FD who received FDgard® versus a control arm of placebo plus commonly used, off-label FD medications experienced a statistically significant reduction in Postprandial Distress Syndrome (PDS) symptoms and near statistical significance in Epigastric Pain Syndrome (EPS) symptoms at 24 hours. In spite of the polypharmacy and use of rescue medications after 48 hours of first dose, FDgard® helped further improve symptoms at 4 weeks.

Specifically, the FDREST™ study showed that at 24 hours, FDgard® improved FD symptoms in patients and provided rapid and significant reduction in EPS and PDS symptoms in the PDS sub-group as well as a statistically significant reduction in EPS and PDS symptoms in the EPS sub-group. At 4 weeks, approximately 75 percent of the EPS and PDS patients in the FDgard® arm reported substantial symptom improvement vs. approximately half in the control arm.

An estimated 62 percent of FD patients suffer from EPS, while an estimated 73 percent of FD patients suffer from PDS. The overlap of EPS and PDS, which are those FD patients who suffer from both syndromes, is estimated to be 35 percent.[1]

FDgard® is specially formulated for the dietary management of FD, which is persistent or recurring indigestion. It is the first product using a patented, breakthrough technology called Site Specific Targeting (SST®) to deliver individually triple-coated, solid-state microspheres of caraway oil and l-Menthol, the primary component in peppermint oil, quickly and reliably where they are needed most in FD — the upper belly.

The three posters with data from the FDREST™ study were selected for presentation at DDW on Saturday, May 6, 2017.

“These study results are uniquely important and represent an advance in the management of Functional Dyspepsia,” said Michael S. Epstein, M.D., F.A.C.G., A.G.A.F., a leading gastroenterologist and Chief Medical Advisor for IM HealthScience®. “We believe that FDgard® possesses anti-inflammatory, analgesic, and gastro-protective properties, which likely are responsible for the rapid relief and steady improvement of FD symptoms in patients even when used as an add-on therapy to commonly used, off-label medications to treat FD, as demonstrated in the FDREST™ study. In particular, many FD symptoms flare within 2 hours after a meal, so the fast action seen in this FDgard® study is an important advance.”

 

FDREST Results

“Functional dyspepsia can have a significant impact on a patient’s quality of life,” said

William D. Chey, M.D., F.A.C.G., the lead study author and Director in the Division of Gastroenterology, Michigan Medicine Gastroenterology Clinic, Ann Arbor, Michigan. “These study results suggest that FDgard® can provide rapid relief to a subset of patients with functional dyspepsia – a condition for which there are few effective treatments.”

Analysis of FDREST™ data showed that treatment with FDgard® resulted in:

Change in Epigastric Pain Syndrome (EPS) and Postprandial Distress Syndrome (PDS) Symptoms In Overall Participants at 24 hours:

  • 14% improvement of EPS symptoms from baseline at 24 hours. Close to statistical significance compared to the control group (P=0.0737).
  • 9.9% reduction of PDS symptoms from baseline at 24 hours. Statistically significant compared to the control group (P=0.0393).

 

Change in Epigastric Pain Syndrome (EPS) and Postprandial Distress Syndrome (PDS) Symptoms In PDS Group at 24 hours:

  • 19.5% reduction of EPS symptoms from baseline at 24 hours. Statistically significant compared to the control group (P=0.0121).
  • 15.8% reduction of PDS symptoms from baseline at 24 hours. Statistically significant compared to the control group (P=0.0225).

 

Change in Epigastric Pain Syndrome (EPS) and Postprandial Distress Syndrome (PDS) Symptoms In EPS Group at 24 hours:

  • 20.7% reduction of EPS symptoms from baseline at 24 hours. Statistically significant compared to the control group (P=0.0028).
  • 13.2% reduction of PDS symptoms from baseline at 24 hours. Statistically significant compared to the control (P=0.0186).

 

Change in the Clinical Global Impressions Scale (CGI, a measure of symptom severity, treatment response and treatment efficacy):

  • At the end of treatment, 77.7% of PDS patients and 72.2% of EPS patients reported either a “much” or “very much” improved assessment of the Clinical Global Impressions (CGI) scale, compared to 50% (P=0.09) and 40% (P=0.046) in the control groups, respectively.
  • EPS patients had a statistically significant reduction in epigastric pain or discomfort symptoms at 24 hours and were objectively better, although measures did not reach statistical significance, compared to the control group, in all measures at 2-14 days and 15-28 days.
  • PDS patients had a statistically significant reduction in sensations of pressure, heaviness, or fullness compared with the control group at 24 hours and were objectively better, although measures did not reach statistical significance, compared to the control group, in all measures at 2-14 days and 15-28 days.

 

Study Design

FDREST™ (Functional Dyspepsia Reduction and Evaluation Safety Trial) was a multi-centered, post-marketing, parallel group, U.S-based study conducted at eight university-based or gastroenterology research-based centers in the U.S. (study period July 1, 2015, to September 14, 2016). The study was designed to compare the efficacy and safety of FDgard®, plus commonly used FD medications vs a control group of placebo plus commonly used, off-label medications prescribed for FD.

  • There were 100 study participants (76% female; 24% male), aged 18-60 (mean age 43.4 years), with symptoms of FD, all of whom met Rome III criteria for FD.
  • They were selected if they met one or both of the following criteria, based on symptoms:
    • Postprandial Distress Syndrome (PDS, early fullness, pressure and heaviness) – Bothersome postprandial fullness or early satiation at least 3 days per week
    • Epigastric Distress Syndrome (EPS, epigastric pain or burning) – Bothersome epigastric pain or burning at least 1 day per week.
  • They had to have at least moderate symptoms (≥4 points on either question of the 7-point Global Overall Symptoms (GOS) scale on at least 4 days during a 14-day screening period. The GOS scale is a self-reported 7-point scale, adapted from a previously validated 5-point scale. With this scale, patients are asked to grade the overall severity of their dyspepsia symptoms, as defined as upper abdominal symptoms over a certain period of time.
  • The study also showed an improvement at 4 weeks in the Clinical Global Impressions (CGI) Scale, a physician-administered measure of symptom severity, treatment response and treatment efficacy.
  • In the trial, study participants took two capsules of FDgard® or matching placebo in the morning and at dinner time 30 to 60 minutes before a meal. FDgard® or placebo was added to each patients existing FD medication regimen, which included proton pump inhibitors (PPIs), histamine receptor 2 antagonists (H2RAs), anticonvulsants, beta blockers, antihistamines, antidepressants/tricyclic antidepressants (TCAs), pain modulators, antacids, and/or antibiotics. In addition, rescue medications (including prokinetics, antiemetics, anticholinergics, laxatives, antidiarrheals, misoprostol, oral antibiotics, probiotics, calcium channel antagonists, NSAIDs, aspirin (>81 mg per day), antispasmodics, narcotic analgesics, sedative hypnotic agents and other medications that may affect the study) were allowed 48 hours after the first dose, if approved by the medical monitor.
  • Over the course of the study, no serious treatment-emergent adverse events were reported.

 

About Functional Dyspepsia (FD)

Approximately 30 percent of adults suffer from dyspepsia, and about half are estimated to have FD, or non-ulcer dyspepsia.[2] This condition can have a negative effect on workplace attendance and productivity, with associated costs estimated in excess of $18 billion annually.[3]

In FD, which is persistent or recurring indigestion, the normal digestive processes are disrupted along with the digestion and absorption of food nutrients. FD is accompanied by symptoms, such as epigastric pain or discomfort, epigastric burning, postprandial fullness, early satiation, bloating in the upper abdomen, nausea and belching. When doctors diagnose FD, they often identify patients as follows: patients should have these symptoms for at least three months with symptom onset six months previously.

 About FDgard® 

FDgard® is medical food designed to address an unmet medical need for products to help in managing FD, which is persistent or recurring indigestion and its accompanying symptoms.  FDgard® capsules contain caraway oil and l-Menthol, the primary component in peppermint oil, for the dietary management of Functional Dyspepsia (FD). With its patented Site Specific Targeting (SST®) technology, pioneered by IM HealthScience®, FDgard® capsules release individually triple-coated, solid-state microspheres of caraway oil and l-Menthol quickly and reliably where they are needed most in FD — the upper belly. The l-Menthol helps with smooth muscle relaxation and caraway oil helps mitigate the effect of gastric acid on the stomach wall and also helps to normalize gallbladder function as well as deliver promotility and analgesic action in the small intestine (the duodenum) and the stomach.[4] [5] [6] In addition to caraway oil and l-Menthol, FDgard® also provides fiber and amino acids (from gelatin protein). These ingredients have additional positive effects on the gut wall and, thus, help toward normalizing digestion and absorption.

Caraway oil and peppermint oil have a history of working in FD. In multiple clinical studies, the combination of caraway oil and peppermint oil has been shown to manage FD and its accompanying symptoms, such as reducing the intensity of epigastric pain, pain frequency, dyspeptic discomfort and reducing the intensity of sensations of pressure, abdominal heaviness and fullness…significantly better than placebo. A randomized, placebo-controlled multicenter study in Europe[7], previously conducted with the same endpoints and measurements as used in FDREST™, had shown the effectiveness of caraway oil and peppermint oil (l-Menthol) in managing FD symptoms. This study was rated as the highest-quality study on the Jadad scale with a rating of 5, which independently assesses the methodological quality of a clinical trial, and is the most widely used assessment in the world.  The study had used the older single-unit, oil-filled capsule technology, which has challenges in rapid and targeted delivery. Targeted delivery to the upper belly is desirable as recent studies have identified this as the area of disturbance in FD. With SST®, it has now become possible to deliver the combination of caraway oil and peppermint oil (l-Menthol) to this site.

The usual adult dose of FDgard® is 2 capsules, as needed, up to two times a day, not to exceed six capsules per day. While FDgard® does not require a prescription, it must be used under medical supervision, since it is a medical food. FDgard® is available to patients in the digestive aisle at most Rite Aid, CVS/pharmacy and Walgreens stores nationwide.

 

About IM HealthScience®

IM HealthScience® (IMH) is the innovator of IBgard® and FDgard® for the dietary management of Irritable Bowel Syndrome (IBS) and Functional Dyspepsia (FD), respectively. It is a privately held company based in Boca Raton, Florida. It was founded in 2010 by a team of highly experienced pharmaceutical research and development and management executives. The company is dedicated to developing products to address gastrointestinal issues where there is a high unmet need. The IM HealthScience® advantage comes from developing products based on its patented, targeted-delivery technologies called Site Specific Targeting (SST®). For more information, visit www.imhealthscience.com to learn about the company, or www.IBgard.com or www.FDgard.com.

 

Data Presented at DDW Poster Session on Functional Dyspepsia, Nausea and Vomiting

Saturday, May 6, 2017

  • (Poster Session #Sa1618) Randomized Controlled Trial to Assess the Efficacy & Safety of Caraway Oil/L-Menthol plus Usual Care Polypharmacy vs. Placebo plus Usual Care Polypharmacy for Functional Dyspepsia 
    • Dr. William Chey, Dr. Brian Lacy, Dr. Brooks Cash, Dr. Michael Epstein and Dr. Syed Shah
  •  (Poster Session #Sa1620) A caraway oil/menthol combination improves functional dyspepsia (FD) symptoms within the first 24 hours: Results of a randomized controlled trial, which allowed usual FD treatments
    • Dr. Brian Lacy, Dr. William Chey, Dr. Brooks Cash, Dr. Michael Epstein and Dr. Syed Shah
  •  (Poster Session #Sa1619) Efficacy of caraway oil/L-menthol plus usual care vs placebo plus usual care, in functional dyspepsia patients with post-prandial distress (PDS) or epigastric pain (EPS) syndromes: Results from a US RCT
    • Dr. William Chey, Dr. Brian Lacy, Dr. Brooks Cash, Dr. Michael Epstein and Dr. Syed Shah

For more information about featured studies, as well as a schedule of availability for featured researchers, please visit www.ddw.org/press.

About Digestive Disease Week® (DDW)

Digestive Disease Week® (DDW) is the largest international gathering of physicians, researchers and academics in the fields of gastroenterology, hepatology, endoscopy and gastrointestinal surgery. Jointly sponsored by the American Association for the Study of Liver Diseases (AASLD), the American Gastroenterological Association (AGA) Institute, the American Society for Gastrointestinal Endoscopy (ASGE) and the Society for Surgery of the Alimentary Tract (SSAT), DDW takes place May 6-9, 2017, at McCormick Place, Chicago, IL. The meeting showcases more than 5,000 abstracts and hundreds of lectures on the latest advances in GI research, medicine and technology. More information can be found at www.ddw.org.

Regulation of Medical Foods

FDgard® is a medical food product and not a drug or dietary supplement.  A medical food is defined by section 5(b)(3) of the Orphan Drug Act (21 U.S.C, 360ee (b)(3) as a “food which is formulated to be consumed or administered internally under the supervision of a physician and which is intended for the specific dietary management of a disease or condition for which distinct nutritional requirements, based on scientific principles, are established by medical evaluation.” Medical foods do not require prior approval by the FDA and are in a unique category separate from drugs or dietary supplements. Medical foods must contain ingredients that are “Generally Recognized As Safe” (GRAS), or are approved food additives, as defined under sections 201(s) and 409 of the Federal Food, Drug and Cosmetic Act.

###

REFERENCE/SOURCE

[1] Talley, N.J. & Ford, A.C. (2015). Functional Dyspepsia. The New England Journal of Medicine, 373, 1853-63. doi: 10.1056/NEJMra1501505.

[2] Copyright © 1997 International Foundation for Functional Gastrointestinal Disorders (IFFGD). All rights reserved. Functional Dyspepsia and IBS: Incidence and Characteristics.

[3] Lacy, B.E., Weiser, K.T., Kennedy, A.T., Crowell, M.D., & Talley, N.J. (2013). Functional dyspepsia: the economic impact to patients. Alimentary Pharmacology & Therapeutics, 38:170-177. doi: 10.111/apt.12355.

[4] Shams, R., Oldfield, E.C., Copare, J., & Johnson, D.A. (2015). Peppermint Oil: Clinical Uses in the Treatment of Gastrointestinal Diseases. JSM Gastroenterology and Hepatology, 3 (1): 1035-1046.

[5] Sun, J. (2007). D-Limonene: Safety & Clinical Applications. Alternative Medicine Review, 12 (3): 259-264.

[6] Goncalves, J.C.R., Alves, A. de Miranda H., de Araujo, A.E.V., Cruz, J.S., & Araujo, D.A.M. (2010). Distinct effects of carvone analogues on the isolated nerve of rats. European Journal of Pharmacology, 645:108-112. doi: 10.1016/j.ejphar.2010.07.027.

[7] May, B., Köhler, S., & Schneider, B. (2000). Efficacy and tolerability of a fixed combination of peppermint oil and caraway oil in patients suffering from functional dyspepsia. Alimentary Pharmacology and Therapeutics, 14 (12), 1671–1677. doi: 10.1046/j.1365-2036.2000.00873.x.

SOURCE

http://www.prnewswire.com/news-releases/results-of-new-clinical-data-presented-at-digestive-disease-week-ddw-a-premier-gastroenterology-meeting-show-unprecedented-symptom-reduction-and-rapid-relief-of-functional-dyspepsia-fd—persistent-or-recurring-indigestion-w-300452368.html

Read Full Post »


University Children’s Hospital Zurich (Universitäts-Kinderspital Zürich), Switzerland – A Prominent Center of Pediatric Research and Medicine

Author: Gail S. Thornton, M.A.

Co-Editor: The VOICES of Patients, Hospital CEOs, HealthCare Providers, Caregivers and Families: Personal Experience with Critical Care and Invasive Medical Procedures

 

University Children’s Hospital Zurich (Universitäts-Kinderspital Zürich —  http://www.kispi.uzh.ch), in Switzerland, is the largest specialized, child and adolescent hospital in the country and one of the leading research centers for pediatric and youth medicine in Europe. The hospital, which has about 220 beds, numerous outpatient clinics, a day clinic, an interdisciplinary emergency room, and a specialized rehabilitation center, is a non-profit private institution that offers a comprehensive range of more than 40 medical sub-specializations, including heart conditions, bone marrow transplantation and burns. There are approximately 2,200 physicians, nurses, and other allied health care and administrative personnel employed at the hospital.

Just as important, the hospital houses the Children’s Research Center (CRC), the first research center in Switzerland that is solely dedicated to pediatric research, and is on par with the largest children’s clinics in the world. The research center provides a strong link between research and clinical experience to ensure that the latest scientific findings are made available to patients and implemented in life-saving therapies. By developing highly precise early diagnoses, innovative therapeutic approaches and effective new drugs, the researchers aim to provide a breakthrough in prevention, treatment and cure of common and, especially, rare diseases in children.

Several significant milestones have been reached over the past year. One important project under way is approval by the hospital management board and Zurich city council to construct a new building, projected to be completed in 2021. The new Children’s Hospital will constitute two main buildings; one building will house the hospital with around 200 beds, and the other building will house university research and teaching facilities.

In the ongoing quest for growing demands for quality, safety and efficiency that better serve patients and their families, the hospital management established a new role of Chief Operating Officer. This new position is responsible for the daily operation of the hospital, focusing on safety and clinical results, building a service culture and producing strong financial results. Greater emphasis on clinical outcomes, patient satisfaction and partnering with physicians, nurses, and other medical and administrative staff is all part of developing a thriving and lasting hospital culture.

Recently, the hospital’s Neurodermatitis Unit in cooperation with Christine Kuehne – Center for Allergy Research and Education (CK-Care), one of Europe’s largest private initiatives in the field of allergology, has won the “Interprofessionality Award” from the Swiss Academy of Medical Sciences.  This award highlights best practices among doctors, nurses and medical staff in organizations who work together to diagnose and treat the health and well-being of patients, especially children with atopic dermatitis and their families.

At the northern end of Lake Zurich and between the mountain summit of the Uetliberg and Zurichberg, Children’s Hospital is located in the center of the residential district of Hottingen.

 

childrens-hospital4childrens-hospital3childrens-hospital2childrens-hospital1

Image SOURCE: Photograph courtesy of Children’s Hospital Zurich (Universitäts-Kinderspital Zürich), Switzerland. Interior and exterior photographs of the hospital.

 

Below is my interview with Hospital Director and Chief Executive Officer Markus Malagoli, Ph.D., which occurred in December, 2016.

How do you keep the spirit of innovation alive? 

Dr. Malagoli: Innovation in an organization, such as the University Children’s Hospital, correlates to a large extent on the power to attract the best and most innovative medical team and administrative people. It is our hope that by providing our employees with the time and financial resources to undertake needed research projects, they will be opened to further academic perspectives. At first sight, this may seem to be an expensive opportunity. However, in the long run, we have significant research under way in key areas which benefits children ultimately. It also gives our hospital the competitive edge in providing quality care and helps us recruit the best physicians, nurses, therapists, social workers and administrative staff.

The Children’s Hospital Zurich is nationally and internationally positioned as highly specialized in the following areas:

  • Cardiology and cardiac surgery: pediatric cardiac center,
  • Neonatal and malformation surgery as well as fetal surgery,
  • Neurology and neurosurgery as well as neurorehabilitation,
  • Oncology, hematology and immunology as well as oncology and stem cell transplants,
  • Metabolic disorders and endocrinology as well as newborn screening, and
  • Combustion surgery and plastic reconstructive surgery.

We provide patients with our special medical expertise, as well as an expanded  knowledge and new insights into the causes, diagnosis, treatment and prophylaxis of diseases, accidents or deformities. We have more than 40 medical disciplines that cover the entire spectrum of pediatrics as well as child and youth surgery.

As an example, for many years, we have treated all congenital and acquired heart disease in children. Since 2004, specialized heart surgery and post-operative care in our cardiac intensive care unit have been carried out exclusively in our child-friendly hospital. A separate heart operation area was set up for this purpose. The children’s heart center also has a modern cardiac catheter laboratory for children and adolescents with all diagnostic and catheter-interventional therapeutic options. Heart-specific non-invasive diagnostic possibilities using MRI are available as well as a large cardiology clinic with approximately 4,500 outpatient consultations per year. In April 2013, a special ward only for cardiac patients was opened and our nursing staff is highly specialized in the care of children with heart problems.

In addition to the advanced medical diagnostics and treatment of children, we also believe in the importance of caring and supporting families of sick children with a focus on their psychosocial well-being. For this purpose, a team of specialized nurses, psychiatrists, psychologists, and social workers are available. Occasionally, the children and their families need rehabilitation and we work with a team of specialists to plan and organize the best in-house or out-patient rehabilitation for the children and their families.

We also provide therapeutic, rehabilitation and social services that encompass nutritional advice, art and expression therapy, speech therapy, physical therapy, psychomotor therapy, a helpline for rare diseases, pastoral care, social counseling, and even hospital clowns. Our hospital teams work together to provide our patients with the best care so they are on the road to recovery in the fastest possible way.

What draws patients to Children’s Hospital?

Dr. Malagoli: Our hospital depends heavily on complex, interdisciplinary cases. For many diagnosis and treatments, our hospital is the last resort for children and adolescents in Switzerland and even across other countries. Our team is fully committed to the welfare of the patients they treat in order to deal with complex medical cases, such as diseases and disorders of the musculo-skeletal system and connective tissue, nervous system, respiratory system, digestive system, and ear, nose and throat, for example.

Most of our patients come from Switzerland and other cantons within the country, yet other patients come from as far away as Russia and the Middle East. Our hospital sees about 80,000 patients each year in the outpatient clinic for conditions, such as allergic pulmonary diseases, endocrinology and diabetology, hepatology, and gastroenterology; about 7,000 patients a year are seen for surgery; and about 37,000 patients a year are treated in the emergency ward.

We believe that parents are not visitors; they belong to the sick child’s healing, growth, and development. This guiding principle is a challenge for us, because we care not only for sick children, but also for their families, who may need personal or financial resources. Many of our services for parents, for example, are not paid by the Swiss health insurance and we depend strongly on funds from private institutions. We want to convey the feeling of security to children and adolescents of all ages and we involve the family in the recovery process.

What are the hospital’s strengths?

Dr. Malagoli: A special strength of our hospital is the interdisciplinary thinking of our teams. In addition to the interdisciplinary emergency and intensive care units, there are several internal institutionalized meetings, such as the uro-nephro-radiological conference on Mondays, the oncological conference and the gastroenterological meeting on Tuesdays,  and the pneumological case discussion on Wednesdays, where complex cases are discussed among our doctors. Foreign doctors are welcome to these meetings, and cases are also discussed at the appropriate external medical conferences.

Can you discuss some of the research projects under way at the Children’s Research Center (CRC)?

Dr. Malagoli: Our Children’s Research Center, the first research center in Switzerland focused on pediatric research, works closely with our hospital team. From basic research to clinical application, the hospital’s tasks in research and teaching is at the core of the Children’s Research Center for many young and established researchers and, ultimately, also for patients.

Our research projects focus on:

  • Behavior of the nervous, metabolic, cardiovascular and immune system in all stages of growth and development of the child’s condition,
  • Etiology (causes of disease) and treatment of genetic diseases,
  • Tissue engineering of the skin and skin care research: from a few cells of a child,  complex two-layered skin is produced in the laboratory for life-saving measures after severe burns and treatment of congenital anomalies of the skin,
  • Potential treatment approaches of the most severe infectious diseases, and
  • Cancer diseases of children and adolescents.

You are making great strides in diagnostic work in the areas of Hematology, Immumology, Infectiology and Oncology. Would you elaborate on this particular work that is taking place at the hospital?

Dr. Malagoli: The Department of Image Diagnostics handles radiological and ultrasonographic examinations, and the numerous specialist labs offer a complete  range of laboratory diagnostics.

The laboratory center makes an important contribution to the clarification and treatment of disorders of immune defense, blood and cancer, as well as infections of all kinds and severity. Our highly specialized laboratories offer a large number of analyzes which are necessary in the assessment of normal and pathological cell functions and take into account the specifics and requirements of growth and development in children and infants.

The lab center also participates in various clinical trials and research projects. This allows on-going validation and finally introducing the latest test methods.

The laboratory has been certified as ISO 9001 by the Swiss Government since 2002 and has met the quality management system requirements on meeting patient expectations and delivering customer satisfaction. The interdisciplinary cooperation and careful communication of the laboratory results are at the center of our activities. Within the scope of our quality assurance measures, we conduct internal quality controls on a regular basis and participate in external tests. Among other things, the work of the laboratory center is supervised by the cantonal medicine committee and Swissmedic organization.

Additionally, the Metabolism Laboratory  offers a wide variety of biochemical and molecular diagnostic analysis, including those for the following areas:

  • Disorders in glycogen and fructose metabolism,
  • Lysosomal disorders,
  • Disorders of biotin and vitamin B12 metabolism,
  • Urea cycle disorders and Maple Syrup Urine Disease (MSUD),
  • Congenital disorders of protein glycosylation, and
  • Hereditary disorders of connective tissue, such as Ehlers-Danlos Syndrome and Marfan Syndrome.

Screening for newborn conditions is equally important. The Newborn Screening Laboratory examines all newborn children in Switzerland for congenital metabolic and hormonal diseases. Untreated, the diseases detected in the screening lead in most cases to serious damage to different organs, but especially to the development of the brain. Thanks to the newborn screening, the metabolic and hormonal diseases that are being sought can be investigated by means of modern methods shortly after birth. For this, only a few drops of blood are necessary, which are taken from the heel on the third or fourth day after birth. On a filter paper strip, these blood drops are sent to the laboratory of the Children’s Hospital Zurich, where they are examined for the following diseases:

  • Phenylketonuria (PKU),
  • Hypothyroidism,
  • MCAD deficiency,
  • Adrenogenital Syndrome (AGS),
  • Galactosemia,
  • Biotinide deficiency,
  • Cystic Fibrosis (CF),
  • Glutaraziduria Type 1 (GA-1), and
  • Maple Syrup Urine Disease (MSUD).

Ongoing physician medical education and executive training is important for the overall well-being of the hospital. Would you describe the program and the courses?

Dr. Malagoli:  We place a high priority on medical education and training with a focus on children, youth, and their families. The various departments of the hospital offer regular specialist training courses for interested physicians at regular intervals. Training is available in the following areas:

  • Anesthesiology,
  • Surgery,
  • Developmental Pediatrics,
  • Cardiology,
  • Clinical Chemistry and Biochemistry,
  • Neuropediatrics,
  • Oncology,
  • Pediatrics, and
  • Rehabilitation.

As a training hospital, we have built an extensive network or relationships with physicians in Switzerland as well as other parts of the world, who take part in our ongoing medical education opportunities that focus on specialized pediatrics and  pediatric surgery. Also, newly trained, young physicians who are in private practice or affiliated with other children’s hospitals often take part in our courses.

We also offer our hospital management and leaders from other organizations professional development in the areas of leadership or specialized competence training. We believe that all executives in leadership or management roles contribute significantly to our success and to a positive working climate. That is why we have developed crucial training in specific, work-related courses, including planning and communications skills, professional competence, and entrepreneurial development.

How is Children’s Hospital transforming health care? 

Dr. Malagoli: The close cooperation between doctors, nurses, therapists and social workers is a key success factor in transforming health care. We strive for comprehensive child care that does not only focus on somatic issues but also on psychological support for patients and their families and social re-integration. However, it becomes more and more difficult to finance all the necessary support services.

Many supportive services, for example, for parents and families of sick children are not paid by health insurance in Switzerland and we do not receive financial support from the Swiss Government. Since 2012, we have the Swiss Diagnosis Related Groups (DRG) guidelines, a new tariff system for inpatient hospital services, that regulates costs for treatment in hospitals all over the country and those costs do not consider the amount of extra services we provide for parents and families as a children’s hospital. Those DRG principles mostly are for hospitals who treat adult patients.

Since you stepped into your role as CEO, how have you changed the way that you deliver health care?

Dr. Malagoli: I have definitely not reinvented health care! Giving my staff the space for individual development and the chance to realize their ideas is probably my main contribution to our success. Working with children is for many people motivating and enriching. We benefit from that, too. Moreover, we have managed to build up a culture of confidence and mutual respect – we call it the “Kispi-spirit”. “Kispi” as abbreviation of “Kinderspital.” Please visit our special recruiting site, which is www.kispi-spirit.ch.

I can think of a few examples where our doctors and medical teams have made a difference in the lives of our patients. Two of our physicians – PD (Privatdozent, a private university teacher) Dr. med. Alexander Moller and Dr. med. Florian Singer, Ph.D. – are involved in the development of new pulmonary functions tests which allow us to diagnose chronic lung diseases at an early stage in young children.

  • Often times, newly born babies have a lung disease but do not show any specific symptoms, such as coughing. One of these new tests measures lung function based on inhaling and exhaling pure oxygen, rather than using the standard spirometry test used in children and adults to assess how well an infant’s lungs work by measuring how much air they inhale, how much they exhale and how quickly they exhale. The new test is currently part of a clinical routine in children with cystic fibrosis as well as in clinical trials in Europe. The test is so successful that the European Respiratory Society presented Dr. med. Singer, Ph.D., with the ‘Pediatric Research Award’ in 2015.
  • Another significant research question among the pediatric pulmonary disease community is how asthma can be diagnosed reliably and at an earlier stage. PD Dr. med. Moller, chief physician of Pneumology at the hospital, has high hopes in a new way to measure exhaled air via mass spectrometry. If it succeeds, it will be able to evaluate changes in the lungs of asthmatics or help with more specific diagnoses of pneumonia.

In what ways have you built greater transparency, accountability and quality improvement for the benefit of patients?

Dr. Malagoli: Apart from the quality measures which are prescribed by Swiss law, we have decided not to strive for quality certifications and accreditations. We focus on outcome quality, record our results in quality registers and compare our outcome internationally with the best in class.

Our team of approximately 2,200 specialized physicians largely comes from Switzerland, although we have attracted a number of doctors from countries such as Germany, Portugal, Italy, Austria, and even Serbia, Turkey, Macedonia, Slovakia, and Croatia.

We recently conducted an employee satisfaction survey, which showed about 88 percent of employees were very satisfied or satisfied with their working conditions at the hospital and the job we are doing with patients and their families. This ranking is particularly gratifying for us as a service provider for the children and families we serve.

How does your volunteer program help families better deal with hospitalized children?

Dr. Malagoli: We have an enormous commitment from volunteers to care for hospitalized children and we are grateful to them. We offer our patients and their families child care, dog therapy, and even parenting by the Aladdin Foundation, a volunteer visiting service for hospitalized children to relieve parents and relatives and help young patients stay in hospital to recover quickly. The volunteers visit the child in the absence of the parents and are fully briefed on the child’s condition and care plan. The handling of care request usually takes no more than 24 hours and is free of charge. The assignments range from one-off visits to daily care for several weeks.

malagoli_m_905

Image SOURCE: Photograph of Hospital Director and Chief Executive Officer Markus Malagoli, Ph.D., courtesy of Children’s Hospital Zurich (Universitäts-Kinderspital Zürich), Switzerland.  

Markus Malagoli, Ph.D.
Director and Chief Executive Officer

Markus Malagoli, Ph.D., has been Hospital Director and Chief Executive Officer of the University Children’s Hospital Zurich (Universitäts-Kinderspital Zürich), since 2007.

Prior to his current role, Dr. Malagoli served as Chairman of Hospital Management and Head of Geriatrics of the Schaffhausen-Akutspital, the only public hospital in the Canton of Schaffhausen, from 2003 through 2007, where he was responsible for 10 departments, including surgery, internal medicine, obstetrics/gynecology, rheumatology/rehabilitation, throat and nose, eyes, radiology, anesthesia, hospital pharmacy and administration. The hospital employs approximately 1,000 physicians, nursing staff, other medical personal, as well as administration and operational services employees. On average, around 9,000 individuals are treated in the hospital yearly. Previously, he was Administrative Director at the Hospital from 1996 through 2003.

Dr. Malagoli began his career at Ciba-Geigy in 1985, spending 11 years in the company. He worked in Business Accounting in Basel, and a few years later, became Head of the Production Information System department in Basel. He then was transferred to Ciba-Geigy in South Africa as Controller/Treasurer and returned to Basel as Project Manager for the SAP Migration Project in Accounting.

Dr. Malagoli received his B.A. degree in Finance and Accounting and a Ph.D. in Business Administration at the University of St. Gallen.

He is a member of the Supervisory Board of Schaffhausen-Akutspital and President of the Ungarbühl in Schaffhausen, a dormitory for individuals with developmental impairments.

Editor’s note:

We would like to thank Manuela Frey, communications manager, University Children’s Hospital Zurich, for the help and support she provided during this interview.

 

REFERENCE/SOURCE

University Children’s Hospital Zurich (Universitäts-Kinderspital Zürich —  http://www.kispi.uzh.ch)

Other related articles

Retrieved from http://www.swisshealth.ch/en/patienten/spitaeler/Kispi.php

Retrieved from http://hospitals.webometrics.info/en/europe/switzerland%20

Retrieved from http://www.gruner.ch/en/projects/university-childrens-hospital-zurich

Retrieved from http://www.ebmt-swiss-ng.org/university-childrens-hospital-zurich.html

Other related articles were published in this Open Access Online Scientific Journal include the following: 

2016

Healthcare conglomeration to access Big Data and lower costs

https://pharmaceuticalintelligence.com/2016/01/13/healthcare-conglomeration-to-access-big-data-and-lower-costs/

A New Standard in Health Care – Farrer Park Hospital, Singapore’s First Fully Integrated Healthcare/Hospitality Complex

https://pharmaceuticalintelligence.com/2016/06/22/a-new-standard-in-health-care-farrer-park-hospital-singapores-first-fully-integrated-healthcarehospitality-complex/

A Rich Tradition of Patient-Focused Care — Richmond University Medical Center, New York’s Leader in Health Care and Medical Education

https://pharmaceuticalintelligence.com/2016/10/17/a-rich-tradition-of-patient-focused-care-richmond-university-medical-center-new-yorks-leader-in-health-care-and-medical-education/

2013

Risk Factor for Health Systems: High Turnover of Hospital CEOs and Visionary’s Role of Hospitals In 10 Years

https://pharmaceuticalintelligence.com/2013/08/08/risk-factor-for-health-systems-high-turnover-of-hospital-ceos-and-visionarys-role-of-hospitals-in-10-years/

Nation’s Biobanks: Academic institutions, Research institutes and Hospitals – vary by Collections Size, Types of Specimens and Applications: Regulations are Needed

https://pharmaceuticalintelligence.com/2013/01/26/nations-biobanks-academic-institutions-research-institutes-and-hospitals-vary-by-collections-size-types-of-specimens-and-applications-regulations-are-needed/

 

 

 

 

Read Full Post »


Pancreatic Cancer Targeted Treatment?

Curator: Larry H. Bernstein, MD, FCAP

 

 

MGH study identifies potential treatment target for pancreatic cancer

Molecular signature found in 30 percent of PDAC tumors, associated with more aggressive cancer

http://www.massgeneral.org/about/pressrelease.aspx?id=1933&

 

Massachusetts General Hospital (MGH) investigators have identified the first potential molecular treatment target for the most common form of pancreatic cancer, which kills more than 90 percent of patients. Along with finding that the tumor suppressor protein SIRT6 is inactive in around 30 percent of cases of pancreatic ductal adenocarcinoma (PDAC), the team identified the precise pathway by which SIRT6 suppresses PDAC development, a mechanism different from the way it suppresses colorectal cancer. The paper will appear in the June 2 issue of Cell and have been published online.

“With the advance of cancer genomics, it has become evident that alterations in epigenetic factors – those that control whether and when other genes are expressed – represent some of the most frequent alterations in cancer,” says Raul Mostoslavsky, MD, PhD, of the MGH Cancer Center, senior author of the report.  “Yet, not many of those factors have been described before, and those that have been identified have not been linked to specific downstream targets.  Not only did more than a third of analyzed PDAC patient samples exhibit the molecular signature we identified, those patients also turned out to have very poor prognoses.”

Among its other functions, SIRT6 is known to control how cells process glucose, and a 2012 study by Mostoslavsky’s team found that its ability to suppress colorectal cancer involves control of a process called glycolysis.  But while that study also found reduced SIRT6 expression in PDAC tumor cells, the current investigation indicated that SIRT6 deficiency promotes PDAC through a different mechanism. Experiments in cell lines and animal models revealed that low SIRT6 levels in PDAC were correlated with increased expression of Lin28b, an oncoprotein normally expressed during fetal development.

Lin28b expression proved to be essential to the growth and survival of SIRT6-deficient PDAC cells and acted by preventing a family of tumor-suppressing mRNAs called let-7 from blocking expression of three genes previously associated with increased aggressiveness and metastasis in pancreatic cancers.  All of these hallmarks – reduced SIRT6, increased Lin28b and reduced let-7 expression – were found in tumor samples from patients who died more quickly.

“A general message from these studies is that cancer cells benefit from modulating epigenetic factors like SIRT6 by acquiring the ability to override normal cellular growth control patterns,” says Mostoslavsky, an associate professor of Medicine at Harvard Medical School and an associate member at the Broad Institute.  “Each tumor type may acquire a unique set of capabilities that may provide tumor-specific growth and survival advantages, which may need to be determined for each kind of cancer.  In terms of our findings regarding PDAC, we are intrigued by the downstream pathways controlled by Lin28b and how they increase aggressiveness and metastasis, and we are hopeful that developing in the future Lin28b inhibitors could benefit this subset of PDAC patients, who currently have very few treatment options.”

 

SIRT6 Suppresses Pancreatic Cancer through Control of Lin28b

Sita Kugel, Carlos Sebastián, Julien Fitamant,…., Alon Goren, Vikram Deshpande, Nabeel Bardeesy, Raul Mostoslavsky

Figure thumbnail fx1
Highlights
  • Loss of SIRT6 cooperates with oncogenic Kras to drive pancreatic cancer
  • SIRT6 regulates the oncofetal protein Lin28b through promoter histone deacetylation
  • Lin28b drives the growth and survival of SIRT6-deficient pancreatic cancer
  • SIRT6 and Lin28b expression define prognosis in specific pancreatic cancer subsets

Chromatin remodeling proteins are frequently dysregulated in human cancer, yet little is known about how they control tumorigenesis. Here, we uncover an epigenetic program mediated by the NAD+-dependent histone deacetylase Sirtuin 6 (SIRT6) that is critical for suppression of pancreatic ductal adenocarcinoma (PDAC), one of the most lethal malignancies. SIRT6 inactivation accelerates PDAC progression and metastasis via upregulation of Lin28b, a negative regulator of the let-7 microRNA. SIRT6 loss results in histone hyperacetylation at theLin28b promoter, Myc recruitment, and pronounced induction of Lin28b and downstream let-7 target genes, HMGA2, IGF2BP1, and IGF2BP3. This epigenetic program defines a distinct subset with a poor prognosis, representing 30%–40% of human PDAC, characterized by reduced SIRT6 expression and an exquisite dependence on Lin28b for tumor growth. Thus, we identify SIRT6 as an important PDAC tumor suppressor and uncover the Lin28b pathway as a potential therapeutic target in a molecularly defined PDAC subset.

 

The multifaceted functions of sirtuins in cancer

Angeliki Chalkiadaki & Leonard Guarente  Affiliations  Corresponding author
Nature Reviews Cancer (2015); 15:608–624     http://dx.doi.org:/10.1038/nrc3985

The sirtuins (SIRTs; of which there are seven in mammals) are NAD+-dependent enzymes that regulate a large number of cellular pathways and forestall the progression of ageing and age-associated diseases. In recent years, the role of sirtuins in cancer biology has become increasingly apparent, and growing evidence demonstrates that sirtuins regulate many processes that go awry in cancer cells, such as cellular metabolism, the regulation of chromatin structure and the maintenance of genomic stability. In this article, we review recent advances in our understanding of how sirtuins affect cancer metabolism, DNA repair and the tumour microenvironment and how activating or inhibiting sirtuins may be important in preventing or treating cancer.

 

Figure 1: Overview of the role of sirtuins in the regulation of cancer metabolism

The inhibitory effects of sirtuin 3 (SIRT3), SIRT4 and SIRT6 on metabolic pathways that drive cancer cells are depicted. In normal cells, SIRT6 functions as a co-repressor for the transcription factors hypoxia-inducible factor 1α (HIF1α…

 

Tumor suppressor p53 cooperates with SIRT6 to regulate gluconeogenesis by promoting FoxO1 nuclear exclusion

Ping Zhanga,1, Bo Tua,1, Hua Wangb , Ziyang Caoa , Ming Tanga , … , Bin Gaob , Robert G. Roederd,2, and Wei-Guo Zhua,e,2
PNAS | July 22, 2014;111(29): 10684–10689 |   http://www.pnas.org/content/111/29/10684.full.pdf  http://www.pnas.org/lookup/suppl/doi:10. 1073/pnas.1411026111/-/DCSupplemental.

In mammalian cells, tumor suppressor p53 plays critical roles in the regulation of glucose metabolism, including glycolysis and oxidative phosphorylation, but whether and how p53 also regulates gluconeogenesis is less clear. Here, we report that p53 efficiently down-regulates the expression of phosphoenolpyruvate carboxykinase (PCK1) and glucose-6-phosphatase (G6PC), which encode rate-limiting enzymes in gluconeogenesis. Cell-based assays demonstrate the p53-dependent nuclear exclusion of forkhead box protein O1 (FoxO1), a key transcription factor that mediates activation of PCK1 and G6PC, with consequent alleviation of FoxO1- dependent gluconeogenesis. Further mechanistic studies show that p53 directly activates expression of the NAD+-dependent histone deacetylase sirtuin 6 (SIRT6), whose interaction with FoxO1 leads to FoxO1 deacetylation and export to the cytoplasm. In support of these observations, p53-mediated FoxO1 nuclear exclusion, down-regulation of PCK1 and G6PC expression, and regulation of glucose levels were confirmed in C57BL/J6 mice and in liver-specific Sirt6 conditional knockout mice. Our results provide insights into mechanisms of metabolism-related p53 functions that may be relevant to tumor suppression.

As the “guardian of the genome,” tumor suppressor p53 has been reported to coordinate diverse cellular responses to a broad range of environment stresses (1) and to play antineoplastic roles by activating downstream target genes involved in DNA damage repair, apoptosis, and cell-cycle arrest (2). Recent studies have indicated broader roles for p53 in mediating metabolic changes in cells under various physiological and pathological conditions (3–7). For example, p53 was reported to influence the balance between glycolysis and oxidative phosphorylation by inducing the p53-induced glycolysis and apoptosis regulator (TIGAR) and by regulating the synthesis of cytochrome c oxidase 2 (SCO2) (3), respectively, thus promoting the switch from glycolysis to oxidative phosphorylation. p53 also may impede metabolism by reducing glucose import (4) or by inhibiting the pentose phosphate pathway (PPP) (5). More recently, context-dependent inhibitory (6) or stimulatory (7, 8) effects of p53 on gluconeogenesis have been reported. It thus is clear that p53 plays important roles in glucose regulation in mammalian cells. Glucose homeostasis is maintained by a delicate balance between intestinal absorption of sugar, gluconeogenesis, and the utilization of glucose by the peripheral tissues, irrespective of feeding or fasting (9). The gluconeogenesis pathway is catalyzed by several key enzymes that include the first and last rate-limiting enzymes of the process, phosphoenolpyruvate carboxykinase (PCK1) and glucose-6-phosphatase (G6PC), respectively. The expression of both PCK1 and G6PC is controlled mainly at the transcription level. For example, the transcription factor forkhead box protein O1 (FoxO1) activates gluconeogenesis through direct binding to the promoters of G6PC and PCK1 (10). A dominant negative FoxO1 lacking its transactivation domain significantly decreases gluconeogenesis (11) whereas FoxO1 ablation impairs fasting- and cAMP-induced PCK1 and G6PC expression (12). Therefore, factors influencing expression of FoxO1 or its binding activity to the PCK1 and G6PC promoters are potential targets for gluconeogenesis regulation. The transcription activity of FoxO family members is regulated by a sophisticated signaling network. Various environmental stimuli cause different posttranslational modifications of FoxO proteins, including phosphorylation, acetylation, ubiquitination, and methylation (13–15). The phosphorylation of FoxO proteins is known to be essential for their shuttling between the nucleus and cytoplasm. For example, kinase Akt/PKB phosphorylates FoxO1 at threonine 24 and at serines 256 and 319, which in turn leads to 14-3-3 binding and subsequent cytoplasmic sequestration. The acetylation of FoxO proteins also affects their trafficking and DNA-binding activities (15–17). Sirtuin (SIRT)1, a homolog of the yeast silent information regulator-2 (Sir2), has been identified as a deacetylase for FoxO proteins (15, 17, 18). Of the seven mammalian sirtuins, SIRT1, SIRT6, and SIRT7 are localized to the nucleus (19), and SIRT6 was recently reported to act as a central player in regulating the DNA damage response, glucose metabolism, and aging (20–26). Using a knockout mouse model, it was found that SIRT6 functions as a corepressor of the transcription factor Hif1α to suppress glucose uptake and glycolysis.

Significance: Beyond its canonical functions in processes such as cell-cycle arrest, apoptosis, and senescence, the tumor suppressor p53 has been increasingly implicated in metabolism. Here, in vitro and in vivo studies establish a role for p53 in gluconeogenesis through a previously unidentified mechanism involving (i) direct activation of the gene encoding the NAD-dependent deacetylase sirtuin 6 (SIRT6), (ii) SIRT6-dependent deacetylation and nuclear exclusion of forkhead box protein O1 (FoxO1), and (iii) downregulation of FoxO1-activated genes (G6PC and PCK1) that are rate-limiting for gluconeogenesis. These results have implications for proposed tumor-suppressor functions of p53 through regulation of metabolic pathways.

Among a variety of other functions, SIRT6 was previously connected to glucose metabolism. For example, SIRT6 acts as a corepressor of the transcription factor Hif1-α to suppress glycolysis (23). Conversely, the deletion of Sirt6 in mice results in severe hypoglycemia (33) whereas the liver-specific deletion of Sirt6 leads to increased glycolysis and triglyceride synthesis (23, 34). Our study adds further evidence that SIRT6 plays an important role in glucose metabolism by connecting p53 transcription activity and gluconeogenesis. Our data also reemphasize a previously established role for SIRT6 in regulating the acetylation state and nuclear localization of FoxO proteins, albeit in a divergent manner. Thus, the Caenorhabditis elegans SIRT6/7 homolog SIR-2.4 was implicated in DAF-16 deacetylation and consequent nuclear localization and function in stress responses (35); and the effect was reported to be indirect and to involve a stress-induced inhibition by SIR-2.4 of CBP-mediated acetylation of DAF-16 that is independent of its deacetylase activity. These results, emphasizing context-dependent SIRT6 mechanisms, contrast with the SIRT6 deacetylase activity requirement for FoxO1 nuclear exclusion in the present study and a likely direct effect of SIRT6 on FoxO1 deacetylation based on their direct interaction, the SIRT6 deacetylase activity requirement, and precedent (15, 17, 18) from direct SIRT1-mediated deacetylation of FoxO proteins.

Despite a high genetic diversity, cancer cells exhibit a common set of functional characteristics, one being the “Warburg effect”: i.e., continuous high glucose uptake and a higher rate of glycolysis than that in normal cells (36). To favor the rapid proliferation requirement for high ATP/ADP and ATP/AMP ratios, cancer cells use large amounts of glucose. p53, as one of the most important tumor suppressors, exerts its antineoplastic function through diverse pathways that include the regulation of glucose metabolism. Thus, p53 regulates glucose metabolism by activation of TIGAR (3), which lowers the intracellular concentrations of fructose-2,6-bisphosphate and decreases glycolysis. On the other hand, p53 activation causes down-regulation of several glycolysisrelated factors such as phosphoglycerate mutase (PGM) (37) and the glucose transporters (4). Expression of p53 also can limit the activity of IκBα and IκBβ, thereby restricting the activation of NFκB and dampening the expression of glycolysis-promoting genes such as GLUT3 (38). As a reverse glycolysis pathway, gluconeogenesis generates glucose from noncarbohydrate precursors and is conceivably essential for tumor cell growth. However, the current study further supports the notion (6) that p53 is also involved in a gluconeogenesis inhibition pathway, which in this case is executed by enhanced SIRT6 expression and subsequent FoxO1 nuclear exclusion. These results raise the interesting possibility that an inhibition of gluconeogenesis may contribute to the tumorsuppressive function of p53.

 

http://www.frontiersin.org/Journal/DownloadFile/1/2496/20065/1/21/fphar-03-00022_pdf

http://www.jcpjournal.org/journal/DOIx.php?id=10.15430/JCP.2013.18.3.221
Keywords : Oncogenes, Tumor suppressors, Glutamine metabolism, Cancer cells … p53 is a well-known protein which is involved in many cellular functionsincluding cell … deprivation activates p53 by regulating protein phosphatase 2A ( PP2A). …. and tumor suppressors may affect glutamine metabolism in cancercells

 

Protein controlling glucose metabolism also a tumor suppressor

Finding supports metabolic strategies to control tumor growth

http://www.massgeneral.org/about/pressrelease.aspx?id=1530    December 6, 2012

A protein known to regulate how cells process glucose also appears to be a tumor suppressor, adding to the potential that therapies directed at cellular metabolism may help suppress tumor growth.  In their report in the Dec. 7 issue of Cell, a multi-institutional research team describes finding that cells lacking the enzyme SIRT6, which controls how cells process glucose, quickly become cancerous.  They also found evidence that uncontrolled glycolysis, a stage in normal glucose metabolism, may drive tumor formation in the absence of SIRT6 and that suppressing glycolysis can halt tumor formation.

“Our study provides solid evidence that SIRT6 may function as a tumor suppressor by regulating glycolytic metabolism in cancer cells,” says Raul Mostoslavsky, MD, PhD, of the Massachusetts General Hospital (MGH) Cancer Center, senior author of the report.  “Critically, our findings indicate that, in tumors driven by low SIRT6 levels, drugs that may inhibit glycolysis – currently a hot research topic among biotechnology companies – could have therapeutic benefits.”

The hypothesis that a switch in the way cells process glucose could set off tumor formation was first proposed in the 1920s by German researcher Otto Warburg, who later received the Nobel Prize for discoveries in cellular respiration.  He observed that, while glucose metabolism is normally a two-step process involving glycolysis in the cellular cytoplasm followed by cellular respiration in the mitochondria, in cancer cells rates of glycolysis are up to 200 times higher.  Warburg’s proposition that this switch in glucose processing was a primary cause of cancer did not hold up, as subsequent research supported the role of mutations in oncogenes, which can spur tumor growth if overexpressed, and tumor suppressors, which keep cell proliferation under control.  But recent studies have suggested that alterations in cellular metabolism may be part of the process through which activated oncogenes or inactivated tumor suppressors stimulate cancer formation.

A 2010 study led by Mostoslavsky found that the absence of SIRT6 – one of a family of proteins called sirtuins that regulate many important biological pathways – appears to “flip the switch” from normal glucose processing to the excess rates of glycolysis seen in cancer cells. The current study was specifically designed to investigate whether SIRT6’s control of glucose metabolism also suppresses tumor formation.  The research team first showed that cultured skin cells from embryonic mice lacking SIRT6 proliferated rapidly and quickly formed tumors when injected into adult mice.  They also confirmed elevated glycolysis levels in both cells lacking SIRT6 and tumor cells and found that formation of tumors through SIRT6 deficiency did not appear to involve oncogene activation.

Analysis of tumor samples from patients found reduced SIRT6 expression in many – particularly in colorectal and pancreatic tumors.  Even among patients whose tumors appeared to be more aggressive, higher levels of SIRT6 expression may have delayed or, for some, prevented relapse.   In a mouse model programmed to develop numerous colon polyps, the researchers showed that lack of intestinal SIRT6 expression tripled the formation of polyps, many of which became invasive tumors.  Treating the animals with a glycolytic inhibitor significantly reduced tumor formation, even in the absence of SIRT6.

“Our results indicate that, at least in certain cancers, inhibiting glycolytic metabolism could provide a strong alternative way to halt cancer growth, possibly acting synergistically with current anti-tumor therapies,” says Mostoslavsky, an assistant professor of Medicine at Harvard Medical School.  “Cancer metabolism has only recently emerged as a hallmark of tumorigenesis, and the field is rapidly expanding.  With the current pace of research and the speed at which some basic discoveries are moving into translational studies, it is likely that drugs targeting cancer metabolism may be available to patients in the near future.”

 

THE HISTONE DEACETYLASE SIRT6 IS A NOVEL TUMOR SUPPRESSOR THAT CONTROLS CANCER METABOLISM

Reprogramming of cellular metabolism is a key event during tumorigenesis. Despite being known for decades (Warburg effect), the molecular mechanisms regulating this switch remained unexplored. Here, we identify SIRT6 as a novel tumor suppressor that regulates aerobic glycolysis in cancer cells. Importantly, loss of SIRT6 leads to tumor formation without activation of known oncogenes, while transformed SIRT6-deficient cells display increased glycolysis and tumor growth, suggesting that SIRT6 plays a role in both establishment and maintenance of cancer. Using a conditional SIRT6 allele, we show that SIRT6 deletion in vivoincreases the number, size and aggressiveness of tumors. SIRT6 also functions as a novel regulator of ribosome metabolism by co-repressing MYC transcriptional activity. Lastly, SIRT6 is selectively downregulated in several human cancers, and expression levels of SIRT6 predict prognosis and tumor-free survival rates, highlighting SIRT6 as a critical modulator of cancer metabolism. Our studies reveal SIRT6 to be a potent tumor suppressor acting to suppress cancer metabolism.

Cancer cells are characterized by the acquisition of several characteristics that enable them to become tumorigenic (Hanahan and Weinberg, 2000). Among them, the ability to sustain uncontrolled proliferation represents the most fundamental trait of cancer cells. This hyperproliferative state involves the deregulation of proliferative signaling pathways as well as loss of cell cycle regulation. In addition, tumor cells need to readjust their energy metabolism to fuel cell growth and division. This metabolic adaptation is directly regulated by many oncogenes and tumor suppressors, and is required to support the energetic and anabolic demands associated with cell growth and proliferation (Lunt and Vander Heiden, 2011).

Alteration in glucose metabolism is the best-known example of metabolic reprogramming in cancer cells. Under aerobic conditions, normal cells convert glucose to pyruvate through glycolysis, which enters the mitochondria to be further catabolized in the tricarboxylic acid cycle (TCA) to generate adenosine-5’-triphosphate (ATP). Under anaerobic conditions, mitochondrial respiration is abated; glucose metabolism is shifted towards glycolytic conversion of pyruvate into lactate. This metabolic reprogramming is also observed in cancer cells even in the presence of oxygen and was first described by Otto Warburg several decades ago (Warburg, 1956; Warburg et al., 1927). By switching their glucose metabolism towards “aerobic glycolysis”, cancer cells accumulate glycolytic intermediates that will be used as building blocks for macromolecular synthesis (Vander Heiden et al., 2009). Most cancer cells exhibit increased glucose uptake, which is due, in part, to the upregulation of glucose transporters, mainly GLUT1 (Yamamoto et al., 1990; Younes et al., 1996). Moreover, cancer cells display a high expression and activity of several glycolytic enzymes, including phospho-fructose kinase (PFK)-1, pyruvate kinase M2, lactate dehydrogenase (LDH)-A and pyruvate dehydrogenase kinase (PDK)-1 (Lunt and Vander Heiden, 2011), leading to the high rate of glucose catabolism and lactate production characteristic of these cells. Importantly, downregulation of either LDH-A or PDK1 decreases tumor growth (Bonnet et al., 2007; Fantin et al., 2006; Le et al., 2010) suggesting an important role for these proteins in the metabolic reprogramming of cancer cells.

Traditionally, cancer-associated alterations in metabolism have been considered a secondary response to cell proliferation signals. However, growing evidence has demonstrated that metabolic reprogramming of cancer cells is a primary function of activated oncogenes and inactivated tumor suppressors (Dang et al., 2012;DeBerardinis et al., 2008; Ward and Thompson, 2012). Despite this evidence, whether the metabolic reprogramming observed in cancer cells is a driving force for tumorigenesis remains as yet poorly understood.

Sirtuins are a family of NAD+-dependent protein deacetylases involved in stress resistance and metabolic homeostasis (Finkel et al., 2009). In mammals, there are seven members of this family (SIRT1-7). SIRT6 is a chromatin-bound factor that was first described as a suppressor of genomic instability (Mostoslavsky et al., 2006). SIRT6 also localizes to telomeres in human cells and controls cellular senescence and telomere structure by deacetylating histone H3 lysine 9 (H3K9) (Michishita et al., 2008). However, the main phenotype SIRT6 deficient mice display is an acute and severe metabolic abnormality. At 20 days of age, they develop a degenerative phenotype that includes complete loss of subcutaneous fat, lymphopenia, osteopenia, and acute onset of hypoglycemia, leading to death in less than ten days (Mostoslavsky et al., 2006). Recently, we have demonstrated that the lethal hypoglycemia exhibited by SIRT6 deficient mice is caused by an increased glucose uptake in muscle and brown adipose tissue (Zhong et al., 2010). Specifically, SIRT6 co-represses HIF-1α by deacetylating H3K9 at the promoters of several glycolytic genes and, consequently, SIRT6 deficient cells exhibit increased glucose uptake and upregulated glycolysis even under normoxic conditions (Zhong et al., 2010). Such a phenotype, reminiscent of the “Warburg Effect” in tumor cells, prompted us to investigate whether SIRT6 may protect against tumorigenesis by inhibiting glycolytic metabolism.

Here, we demonstrate that SIRT6 is a novel tumor suppressor that regulates aerobic glycolysis in cancer cells. Strikingly, SIRT6 acts as a first hit tumor suppressor and lack of this chromatin factor leads to tumor formation even in non-transformed cells. Notably, inhibition of glycolysis in SIRT6 deficient cells completely rescues their tumorigenic potential, suggesting that enhanced glycolysis is the driving force for tumorigenesis in these cells. Furthermore, we provide new data demonstrating that SIRT6 regulates cell proliferation by acting as a co-repressor of c-Myc, inhibiting the expression of ribosomal genes. Finally, SIRT6 expression is downregulated in human cancers, strongly reinforcing the idea that SIRT6 is a novel tumor suppressor.

…..

In addition to controlling glucose metabolism in cancer cells, our current work unravels a novel function of SIRT6 as a regulator of ribosomal gene expression. One of the main features of cancer cells is their high proliferative potential. In order to proliferate, cancer cells readjust their metabolism to generate biosynthetic precursors for macromolecular synthesis (Deberardinis et al., 2008). However, protein synthesis also requires the activation of a transcriptional program leading to ribosome biogenesis and mRNA translation (van Riggelen et al., 2010). As a master regulator of cell proliferation, MYC regulates ribosome biogenesis and protein synthesis by controlling the transcription and assembly of ribosome components as well as translation initiation (Dang et al., 2012; van Riggelen et al., 2010). Our results show that SIRT6 specifically regulates the expression of ribosomal genes. In keeping with this, SIRT6-deficient tumor cells exhibit high levels of ribosomal protein gene expression. Beyond ribosome biosynthesis, MYC regulates glucose and glutamine metabolism (Dang et al., 2012). Our results show that glutamine – but not glucose – metabolism is rescued in SIRT6-deficient/MYC knockdown cells, suggesting that SIRT6 and MYC might have redundant roles in regulating glucose metabolism.

Overall, our results indicate that SIRT6 represses tumorigenesis by inhibiting a glycolytic switch required for cancer cell proliferation. Inhibition of glycolysis in SIRT6-deficient cells abrogates tumor formation, providing proof of concept that inhibition of glycolytic metabolism in tumors with low SIRT6 levels could provide putative alternative approaches to modulate cancer growth. Furthermore, we uncover a new role for SIRT6 as a regulator of ribosome biosynthesis by co-repressing MYC transcriptional activity. Our results indicate that SIRT6 sits at a critical metabolic node, modulating both glycolytic metabolism and ribosome biosynthesis (Figure 7L). SIRT6 deficiency deregulates both pathways, leading to robust metabolic reprogramming that is sufficient to promote tumorigenesis bypassing major oncogenic signaling pathway activation.

 

Lack of cellular enzyme triggers switch in glucose processing

Understanding mechanism underlying SIRT6 activity may help treat diabetes, cancer

http://www.massgeneral.org/about/pressrelease.aspx?id=1196   January 21, 2010

A study investigating how a cellular enzyme affects blood glucose levels in mice provides clues to pathways that may be involved in processes including the regulation of longevity and the proliferation of tumor cells. In their report in the January 22 issue of Cell, a Massachusetts General Hospital (MGH)-based team of researchers describes the mechanism by which absence of the enzyme SIRT6 induces a fatal drop in blood sugar in mice by triggering a switch between two critical cellular processes.

“We found that SIRT6 functions as a master regulator of glucose levels by maintaining the normal processes by which cells convert glucose into energy,” says Raul Mostoslavsky, MD, PhD, of the MGH Cancer Center, who led the study. “Learning more about how this protein controls the way cells handle glucose could lead to new approaches to treating type 2 diabetes and even cancer.”

SIRT6 belongs to a family of proteins called sirtuins, which regulate important biological pathways in organisms from bacteria to humans. Originally discovered in yeast, sirtuins in mammals have been shown to have important roles in metabolic regulation, programmed cell death and adaptation to stress. SIRT6 is one of seven mammalian sirtuins, and Mostoslavsky’s team previously showed that mice lacking the protein die in the first month of life from acute hypoglycemia. The current study was designed to investigate exactly how lack of SIRT6 causes this radical drop in blood sugar.

Normally cells convert glucose into energy through a two-step process. The first stage called glycolysis takes place in the cytoplasm, where glucose is broken down into an acid called pyruvate and a few molecules of ATP, the enzyme that provides the energy to power most biological processes. Pyruvate is taken into cellular structures called mitochondria, where it is further processed to release much greater amounts of ATP through a process called cellular respiration.

In a series of experiments in mouse cells, the researchers showed that SIRT6-deficiency hypoglycemia is caused by increased cellular uptake of glucose and not by elevated insulin levels or defects in the absorption of glucose from food. They then found increased levels of glycolysis and reduced mitochondrial respiration in SIRT6-knockout cells, something usually seen when cells are starved for oxygen or glucose, and showed that activation of the switch from cellular respiration to glycolysis is controlled through SIRT6’s regulation of a protein called HIF1alpha. Normally, SIRT6 represses glycolytic genes through its role as a compactor of chromatin – the tightly wound combination of DNA and a protein backbone that makes up chromosomes. In the absence of SIRT6, this structure is opened, causing activation of these glycolytic genes. The investigators’ finding increased expression of glycolytic genes in living SIRT6-knockout mice – which also had elevated levels of lactic acid, characteristic of a switch to glycolytic glucose processing – supported their cellular findings.

Studies in yeast, worms and flies have suggested a role for sirtuins in aging and longevity, and while much of the enzymes’ activity in mammals is unclear, SIRT6’s control of critical glucose-metabolic pathways could signify a contribution to lifespan regulation. Elevated glycolysis also is commonly found in tumor cells, suggesting that a lack of SIRT6 could contribute to tumor growth. Conversely, since knocking out SIRT6 causes blood sugar to drop, limited SIRT6 inhibition could be a novel strategy for treating type 2 diabetes.

“There’s a lot we still don’t know about SIRT6,” adds Mostoslavsky, who is an assistant professor of Medicine at Harvard Medical School. “We need to identify the factors that interact with SIRT6 and determine how it is regulated; investigate whether it acts as a tumor suppressor and how it might help lower glucose levels in diabetes; and determine its target organs in living animals, all of which we are investigating.”

 

A tale of metabolites: the crosstalk between chromatin and energy metabolism

Mitochondrial metabolism influences histone and DNA modifications by retrograde signaling and activation of transcriptional programs. Considering the high number of putative sites for acetylation and methylation in chromatin, we propose in this Perspective that epigenetic modifications might impinge on cellular metabolism by affecting the pool of acetyl-CoA and SAM.

Metabolism can be defined as the sum of chemical reactions that occur within a cell to sustain life. It is also the way that a cell interacts with energy sources: in other words, it is the coordination of energy intake, its utilization and storage that ultimately allows growth and cell division. In animal cells, mitochondria have evolved to become the most efficient system to generate energy. This organelle consumes carbon sources via oxidative phosphorylation to produce ATP, the energy currency of the cell. Additionally, the mitochondria produces intermediate metabolites for the biosynthesis of DNA, proteins and lipids.

Under basic dividing conditions, uptake of nutrients is tightly regulated through growth signaling pathways, thus differentiated cells engage in oxidative metabolism, the most efficient mechanism to produce energy from nutrients. Cells metabolize glucose to pyruvate through glycolysis in the cytoplasm, and this pyruvate is then oxidized into CO2 through the mitochondrial TCA cycle. The electrochemical gradient generated across the inner mitochondrial membrane facilitates ATP production in a highly efficient manner. Studies in recent years indicate that under conditions of nutrient excess, cells increase their nutrient uptake, adopting instead what is known as aerobic glycolysis, an adaptation that convert pyruvate into lactate, enabling cells to produce intermediate metabolites to sustain growth (anabolic metabolism) (1). Interestingly, most cancer cells undergo the same metabolic switch (Warburg Effect), a unique evolutionary trait that allows them to grow unabated. Although aerobic glycolysis generates much less ATP from glucose compared to oxidative phosphorylation, it provides critical intermediate metabolites that are used for anaplerotic reactions, and therefore is an obligatory adaptation among highly proliferative cells. In response to variations in nutrient availability, cells regulate their metabolic output, coordinating biochemical reactions and mitochondrial activity by altering transcription of mitochondrial genes through both activation of transcription factors, such as PGC1α, and chromatin modulators that exert epigenetic changes on metabolic genes.

Mitochondrial dysfunction has been implicated in aging, degenerative diseases and cancer. Proper mitochondrial function can be compromised by the accumulation of mutations in mitochondrial DNA that occur during aging. In addition, reactive oxygen species (ROS) produced during oxidative phosphorylation can promote oxidative damage to DNA, protein and lipids, in turn adversely affecting global cellular functions. In recent years, several studies have illustrated a novel unexpected link between metabolism and gene activity: fluctuations in mitochondrial and cytoplasmic metabolic reactions can reprogram global metabolism by means of impacting epigenetic dynamics. These studies will be briefly summarized in the first part of this article. In the second part, we will propose a provocative novel hypothesis: the crosstalk between metabolism and epigenetics is a two-way street, and defects in chromatin modulators may affect availability of intermediate metabolites, in turn influencing energy metabolism.

Metabolism impacts epigenetics

A regulated crosstalk between metabolic pathways in the mitochondria and epigenetic mechanisms in the nucleus allows cellular adaptations to new environmental conditions. Fine-tuning of gene expression is achieved by changes in chromatin dynamics, including methylation of DNA and posttranslational modifications of histones: acetyl, methyl and phosphate groups can be added by acetyltransferases, methyltransferases and kinases, respectively, to different residues on histones. Given the number of residues that can potentially undergo modifications in histone tails and in the DNA, it is reasonable to consider that metabolic changes affecting the availability of these metabolites will impact epigenetics (as discussed below).

Recently, acetylation of proteins was revealed to be as abundant as phosphorylation (2). This posttranslational modification involves the covalent binding of an acetyl group obtained from acetyl-CoA to a lysine. In histones, acetylation can modify higher order chromatin structure and serve as a docking site for histone code readers. Recent mass spectrometry studies have uncovered the complete acetylome in human cells and revealed that protein acetylation occurs broadly in the nucleus, cytoplasm and mitochondria, affecting more than 1700 proteins (2). Acetylation of proteins depends on the availability of acetyl-CoA in each cellular compartment, but this metabolite is produced in the mitochondria and cannot cross the mitochondrial membrane. In single cell eukaryotes, the pool of acetyl groups required for histone acetylation comes from the production of acetyl-CoA by the enzyme acetyl-CoA synthetase (Acs2p), which is responsible of converting acetate into acetyl-CoA. In mammalian cells, although they have a homolog enzyme to Acs2p, AceCS1, the majority of acetyl-CoA is produced from mitochondrion-derived citrate by the enzyme adenosine triphosphate (ATP)-citrate lyase (ACL) (3). ACL is present in the cytoplasm and in the nucleus, and is responsible for the production of acetyl-CoA from citrate in both compartments. Citrate is generated in the metabolism of glucose and glutamine in the TCA cycle. In contrast to acetyl-CoA, citrate can cross the mitochondrial membrane and diffuse through the nuclear pores into the nucleus, where it can be converted into acetyl-CoA by ACL. Wellen and colleagues found that ACL is required for acetylation of histones under normal growth conditions; knockdown of ACL decreases the pool of acetyl-CoA in the nucleus and reduces the level of histone acetylation (3). Strikingly, reduction in histone acetylation occurs preferentially around glycolytic genes, leading to downregulation of their transcription and therefore inhibition of glycolysis. These observations reveal a process where glucose metabolism dictates histone acetylation that in a feedback mechanism controls the rate of glycolysis.

Notably, deacetylation of histones also exhibits a metabolic influence. Deacetylation of histones is achieved by class I and class II histone deacetylases (HDACs) and by a separate class (class III), also known as sirtuins. Sirtuins use NAD+ as a cofactor for deacetylation, and the ratio of NAD+/NADH regulates their activity. In diets rich in carbohydrates, growth factors stimulate cellular glucose uptake and the production of energy is carried out through glycolysis. In this context, the NAD+/NADH ratio decreases, in turn inhibiting, in theory, sirtuins in the cytoplasm (Sirt2) and nucleus (Sirt1, Sirt6 and Sirt7). In fact, low Sirt1 and Sirt6 activity generates a global increase in protein acetylation. Interestingly, Sirt6, which is exclusively nuclear, deacetylates H3K9 Hif1α target genes, repressing their transcription. Since most of these genes are glycolytic, deacetylation of histones by Sirt6 modulates glycolysis. Indeed, SIRT6-deficient mice experience a dramatic increase in glucose uptake for glycolysis, triggering a fatal hypoglycemia in few weeks (4).

In animal cells, both histone acetylation and deacetylation are under the control of glucose metabolism through the availability of acetyl-CoA and NAD+, respectively. However, is this metabolic control restricted to acetylation, or can other reactions in the nucleus be influenced by the energy status of the cell?

Histone methyltransferases (HMTs) use S-adenosylmethionine (SAM) to transfer a methyl group onto lysine and arginine residues on histone tails. SAM is produced from methionine by the enzyme S-adenosyl methionine transferase (MAT) in a reaction that uses ATP. The recent finding of MAT in the nucleus suggests that the SAM pool could also be controlled locally in this compartment (5). The reverse reaction catalyzed by histone demethylases (HDMs) uses flavin adenine dinucleotide (FAD+) and α-ketoglutarate as coenzymes. FAD is a common redox coenzyme that exists in two different redox states. In its reduced state, FADH2 is a carrier of energy and when oxidized, FAD+ is consumed in the oxidation of succinate to fumarate by the enzyme succinate dehydrogenase (complex II) in one of the last steps of the TCA cycle. On the other hand, α-ketoglutarate is an intermediate in the TCA cycle. It is generated from isocitrate by the enzymes isocitrate dehydrogenase 1 and 2 (IDH1-cytosolic and IDH2-mitochondrial) (Figure 1A–B). Based on these findings, it is easy to infer that the amount of coenzymes used for histone methylation and demethylation could also be controlled by metabolic reactions. Moreover, the different cellular compartments compete for the same metabolites. Indeed, changes in diet that affect the biosynthesis of SAM, FAD and α-ketoglutarate in the mitochondria and cytoplasm have been shown to impact histone methylation (6).

An external file that holds a picture, illustration, etc. Object name is nihms447752f1.jpg

Figure 1   A) Diagram depicting two-way crosstalk between metabolites in cytoplasm/mitochondria and chromatin.

More recently, some of the metabolic enzymes responsible for producing cofactors for nuclear biochemical reactions have been found mutated in cancer. For instance, IDH1 and IDH2 somatic mutations are recurrent in gliomas and acute myeloid leukemias (AML). These mutations lead not only to a decreased production of α-ketoglutarate but also to a new activity: α-ketoglutarate is in fact converted into 2-hydroxyglutarate (2-HG), a metabolite rarely found in normal cells. The new metabolite is a competitive inhibitor of α-ketoglutarate-dependent dioxygenase enzymes, including the Jumonji C (JmjC) domain containing histone demethylases and the recently discovered TET family of 5-methylcytosine (5mC) hydroxylases involved in DNA demethylation (7). By inhibiting JmjC and TET enzymes, the aberrant production of 2-HG generates a genome-wide histone and DNA hypermethylation phenotype. This is considered to be, at least in part, at the origin of tumorigenesis in IDH1 and IDH2 mutated cells and for this reason, 2-HG may earn its place as an oncometabolite. The discovery that mutations in metabolic enzymes may influence tumorigenesis by means of controlling genome-wide epigenetic changes caused a paradigm shift, indicating that such metabolic abnormalities may affect cancer beyond the Warburg Effect.  ….

Chromatin modifications and cellular metabolism are tightly connected. Thus far the only aspects that have been considered are the retrograde signaling, with mitochondrial metabolites affecting histone modifications, and the anterograde transcriptional regulation of metabolism. A third aspect of the link between nucleus and metabolism has been, in our opinion, omitted so far: a direct influence of chromatin on acetyl-CoA and SAM availability, which may have an essential role also in cancer establishment and development (Figure 1A–B). Notably, a shift towards glycolytic metabolism is now considered a hallmark of cancer cells. It is also true that multiple tumors carry mutations in chromatin modifiers. However, new studies suggest that those two processes may be much more intertwined that previously appreciated, further blurring the limits on their respective roles in tumorigenesis. There is no doubt that changes in metabolite availability can drastically impact chromatin modifications. We believe that the opposite may be true as well. At least in mouse models, deficiency in two chromatin modifiers, SIRT6 and Jhdm2, causes drastic metabolic abnormalities. Even though some of those phenotypes depend on changes in gene-expression, we would like to propose that severe attrition of metabolite pools might as well play a role, a possibility that awaits experimental proof.

……

 

Investigators at UC San Diego say that when they blocked a well known signaling molecule that plays a major role in driving colorectal cancer, an escape pathway emerged that allowed tumors to continue to grow.

The pathway they explored, ERK1/2, is a problem for about a third of all colorectal cancer patients, says Petrus R. de Jong, MD, PhD, a co-first author on the paper.

“Since we were genetically deleting the ERK1/2 pathway, we expected to see less cell proliferation,” said de Jong. “Instead, the opposite occurred. There was more cell growth and loss of organization within the cells.”

The problem was ERK5, the investigators add. And when that was blocked as well in animal models and cell lines for the disease, the combination approach proved more effective in halting cancer growth.

“If you block one pathway, cancer cells usually mutate and find another pathway that ultimately allows for a recurrence of cancer growth,” said co-first author Koji Taniguchi. “Usually, mutations occur over weeks or months. But other times, as in this case, the tumor does not need to develop mutations to find an escape route from targeted therapy. When you find the compensatory pathway and block both, there is no more escape.”

 

GEN News Highlights    May 18, 2016   http://www.genengnews.com/gen-news-highlights/blocking-cancer-signaling-leads-to-discovery-of-new-tumor-promoting-pathway/81252738/
Blocking Cancer Signaling Leads to Discovery of New Tumor-Promoting Pathway

 Immunofluorescent staining of intestinal epithelium tissue shows cell growth (green). In a normal mouse model (left), cell growth is controlled, but in a mouse model with the ERK1/2 pathway blocked (right) increased cell proliferation and loss of organization occurred. [UC San Diego Health]

An international research team lead by scientists at the University of California San Diego School of Medicine uncovered some surprising results while investigating a potential therapeutic target for the ERK1 and two pathways. These signaling pathways are widely expressed and known to drive cancer growth in one-third of patients with colorectal cancer (CRC). The UCSD team found that an alternative pathway immediately emerges when ERK1/2 is halted, thus allowing tumor cell proliferation to continue.

“Since we were genetically deleting the ERK1/2 pathway, we expected to see less cell proliferation,” explained co-lead study author Petrus R. de Jong, M.D., Ph.D., translational scientist at Sanford Burnham Prebys Medical Discovery Institute. “Instead, the opposite occurred. There was more cell growth and loss of organization within the cells.”

The exciting part of this new study is investigators found that treating both ERK1/2 and the compensatory pathway ERK5 concomitantly with a combination of drug inhibitors halted CRC growth more effectively in both mouse models and human CRC cell lines.

“We show that loss of Erk1/2 in intestinal epithelial cells results in defects in nutrient absorption, epithelial cell migration, and secretory cell differentiation,” the authors wrote. “However, intestinal epithelial cell proliferation is not impeded, implying compensatory mechanisms. Genetic deletion ofErk1/2 or pharmacological targeting of MEK1/2 results in supraphysiological activity of the ERK5 pathway. Furthermore, targeting both pathways causes a more effective suppression of cell proliferation in murine intestinal organoids and human CRC lines.”

The findings from this study were published recently in Nature Communications in an article entitled “ERK5 Signalling Rescues Intestinal Epithelial Turnover and Tumour Cell Proliferation upon ERK1/2 Abrogation.”

The ERK pathway plays a critical role in embryonic development and tissue repair because it instructs cells to multiply and start dividing, but when overactivated cancer growth often occurs.

“Therapies aimed at targeting ERK1/2 likely fail because this mechanism is allowing proliferation through a different pathway,” noted senior study author Eyal Raz, M.D., professor of medicine at UC San Diego School of Medicine. “Previously, ERK5 didn’t seem important in colorectal cancer. This is an underappreciated escape pathway for tumor cells. Hence, the combination of ERK1/2 and ERK5 inhibitors may lead to more effective treatments for colorectal cancer patients.”

Currently, there are 1.2 million people living with CRC in the United States, making it the third most common cancer among men and women. In 2016 alone, an estimated 134,490 new cases are expected to be diagnosed, so understanding the molecular mechanisms that drive tumor promotion are paramount to treating this disease effectively.

“If you block one pathway, cancer cells usually mutate and find another pathway that ultimately allows for a recurrence of cancer growth,” remarked co-lead study author Koji Taniguchi, M.D., Ph.D., senior researcher at the Keio University School of Medicine in Tokyo. “Usually, mutations occur over weeks or months. But other times, as in this case, the tumor does not need to develop mutations to find an escape route from targeted therapy. When you find the compensatory pathway and block both, there is no more escape.”

The researchers were excited by their findings but urged caution at over interpretation of their initial findings and suggested that other classes of inhibitors be tested in combination with ERK5 inhibitors in human CRC cells in preclinical mouse models before any patient trial can begin.

 

ERK5 signalling rescues intestinal epithelial turnover and tumour cell proliferation upon ERK1/2 abrogation

Petrus R. de JongKoji TaniguchiAlexandra R. HarrisSamuel BertinNaoki TakahashiJen DuongAlejandro D. CamposGarth PowisMaripat CorrMichael Karin & Eyal Raz
Nature Communications 7, Article number:11551  doi:10.1038/ncomms11551

The ERK1/2 MAPK signalling module integrates extracellular cues that induce proliferation and differentiation of epithelial lineages, and is an established oncogenic driver, particularly in the intestine. However, the interrelation of the ERK1/2 module relative to other signalling pathways in intestinal epithelial cells and colorectal cancer (CRC) is unclear. Here we show that loss of Erk1/2in intestinal epithelial cells results in defects in nutrient absorption, epithelial cell migration and secretory cell differentiation. However, intestinal epithelial cell proliferation is not impeded, implying compensatory mechanisms. Genetic deletion of Erk1/2 or pharmacological targeting of MEK1/2 results in supraphysiological activity of the ERK5 pathway. Furthermore, targeting both pathways causes a more effective suppression of cell proliferation in murine intestinal organoids and human CRC lines. These results suggest that ERK5 provides a common bypass route in intestinal epithelial cells, which rescues cell proliferation upon abrogation of ERK1/2 signalling, with therapeutic implications in CRC.

The extracellular signal-regulated kinases 1 and 2 (ERK1/2) are part of the classical family of mammalian mitogen-activated protein kinases (MAPKs), which also include three c-Jun amino-terminal kinases (JNK1/2/3), four p38 isoforms and its lesser-known counterpart, ERK5. The serine/threonine kinases ERK1 (MAPK3, also known as p44 MAPK) and ERK2 (MAPK1, also known as p42 MAPK) show 83% amino acid identity, are ubiquitously expressed and typically activated by growth factors and phorbol esters, whereas the p38 and JNK pathways are mainly activated by inflammatory cytokines and stress1. MAPKs are involved in regulation of mitosis, gene expression, cell metabolism, cell motility and apoptosis. ERK1/2 are activated by MEK1 and MEK2, which themselves are activated by Raf-1, A-Raf or B-Raf1, 2. Ras proteins (K-Ras, H-Ras or N-Ras) are small GTPases that can be activated by receptor tyrosine kinases (RTKs) or G-protein coupled receptors (GPCRs), which recruit Raf proteins to the plasma membrane where they are activated. Together, these modules constitute the Ras–Raf–MEK–ERK pathway3.

The activation of ERK1/2 results in their nuclear translocation where they can phosphorylate a variety of nuclear targets such as Elk-1, c-Fos and c-Myc1, in addition to p90 ribosomal S6 kinases (p90RSKs) and mitogen- and stress-activated protein kinases, MSK1/2. The full repertoire of substrates for ERK1/2 consists of at least 160 cellular proteins4. These proteins are typically involved in the regulation of cell proliferation—more specifically, G1/S-phase cell cycle progression—and differentiation. However, their cellular effects are context-dependent and determined by the spatial and temporal dynamics of ERK1/2 activity5, which are highly regulated by scaffolding proteins and phosphatases3, 6, 7.

Despite vast literature on the role of ERK1/2 in cell proliferation, the absolute requirement of this signalling module in rapidly dividing tissues relative to other signalling pathways is unknown. The small intestinal epithelium is particularly suitable to address this question given the short (4–8 days) and dynamic life cycle of intestinal epithelial cells (IECs). Lgr5+ intestinal stem cells at the intestinal crypt base produce transit-amplifying cells, which then undergo a number of proliferative cycles before terminal differentiation into absorptive enterocytes at the crypt–villus border. Enterocytes then migrate to the villus tip where they undergo anoikis and are shed into the gut lumen8. All of these cellular events are tightly coordinated by the Wnt, Notch, bone morphogenetic protein (BMP) and Hedgehog pathways9, whereas the roles of ERK1/2 remain to be charted. In the intestines, the ERK1/2 pathway is likely activated by autocrine and paracrine factors downstream of RTKs, such as epidermal growth factor receptor (EGFR)10, and by exogenous microbial-derived substrates that signal through the Toll-like receptor (TLR)/MyD88 pathway11.

To study the effects of ERK1/2 in the adult intestinal epithelium, we generated mice with a conditional (IEC-specific) and tamoxifen-inducible deletion of Erk2 on the Erk1−/− background, which completely abrogates this pathway. We show that the ERK1/2 signalling module, surprisingly, is dispensable for IEC proliferation. Genetic deletion of Erk1/2 in primary IEC or treatment of colorectal cancer (CRC) cell lines with MEK1/2 inhibitors results in compensatory activation of the ERK5 pathway. Moreover, the treatment of human CRC lines with a combination of MEK1/2 and ERK5 inhibitors is more efficacious in the inhibition of cancer cell growth. Thus, compensatory signalling by ERK5 suggests a potential rescue pathway that has clinical implications for targeted therapy in colorectal cancer.

….

Figure 1: Wasting disease associated with malabsorption in Erk1/2ΔIEC mice.

ERK1/2ΔIEC causes wasting and enterocyte dysfunction

Here we show that ERK1/2 signalling in mouse intestinal epithelium is dispensable for cell proliferation, while it resulted in abnormal differentiation of enterocytes, wasting disease and ultimately lethality (Fig. 1). Consistent with these findings, ERK1/2 MAPKs were shown to be associated with the enterocyte brush border and activated upon RTK stimulation or feeding27 or electrical field stimulation in polarized epithelium28. This seems at odds with literature that suggest that maintained ERK1/2 signalling precludes enterocyte differentiation29, 30. A possible explanation for this discrepancy could be that cycling IEC in the transit amplifying zone of the crypt require relatively high levels of active ERK1/2, which is readily blocked by pharmacological intervention, whereas a transition to low level ERK1/2 activity in IEC migrating into the villus compartment promotes the absorptive enterocyte differentiation program that is only perturbed upon complete genetic deletion of Erk1/2. Little is known about the role of ERK1/2 signalling in the life cycle of secretory cells in the gut. A recent report by Heuberger et al.15 described that IEC-specific deletion of non-receptor tyrosine phosphatase, Shp2, resulted in the loss of p-ERK1/2 levels in the small intestine. This coincided with an increased number of Paneth cells at the expense of goblet cells in the small intestine, as well as shortening of villi. They also observed the strongest staining for epithelial p-ERK1/2 in the TA zone. This p-ERK1/2+ staining pattern and the architectural organization of the TA zone were lost in Shp2 knockout mice. Interestingly, the deleterious effects of Shp2 deficiency were rescued by expression of constitutively active MEK1. A model was proposed in which the balance between Wnt/β-catenin and MAPK signalling determines Paneth cell versus goblet cell differentiation, respectively15. This proposed crucial role for ERK1/2 MAPK signalling in intestinal secretory cell differentiation is consistent with our observations inERK1/2ΔIECmice.

Migration and differentiation are functionally intertwined in the intestines, as demonstrated by the immature phenotype of mislocalized Paneth cells observed in ΔIEC mice (Fig. 2). Critical to epithelial cell migration is proper cytoskeleton reorganization mediated by the small GTPases of the Rho family, cell polarization regulated by Cdc42 and dynamic adhesion through cell–matrix and cell–cell interaction via integrin/FAK/Src signalling31. The ERK1/2 module is used as a downstream effector of many of these pathways in the intestine, including Rho GTPases32, FAK33and Src34, and has been suggested to promote cell motility33, 35. RTK signalling also contributes to cell migration, for example, Eph–Ephrin receptor interactions are crucial for correct positioning of Paneth cells36. Ephrin receptor-induced epithelial cell migration has been shown to be mediated by Src and ERK1/2 activation37, 38, which may explain the Paneth cell mislocalization observed in ΔIEC mice. In summary, the ERK1/2 module is indispensable for full maturation of both absorptive enterocytes and the secretory lineage (Fig. 7a), confirming its crucial role in the integration of cellular cues required for determination of epithelial cell fate.

Figure 7: Roles of ERK1/2 and ERK5 in intestinal homeostasis and tumorigenesis.

Roles of ERK1/2 and ERK5 in intestinal homeostasis and tumorigenesis.

(a) When the ERK1/2 pathway is intact, extracellular cues that are transduced via RTKs or GPCRs activate Ras under physiological conditions, or alternatively, Ras is constitutively active in colorectal cancer (RasΔ*), which preferentially activates the Raf–MEK1/2–ERK1/2 module. The nuclear and transcriptional targets of ERK1/2 are crucial for enterocyte and secretory cell differentiation, IEC migration, as well as cell proliferation under homeostatic and oncogenic conditions. Importantly, ERK1/2 activation also results in the activation of negative feedback mechanisms that suppress its upstream kinases (for example, RTKs, son of sevenless, Raf) and activate dual specificity phosphatases (DUSPs), resulting in the silencing of the ERK5 module. (b) Upon abrogation of MEK1/2 or genetic knockout ofErk1/2, the lack of negative feedback mechanisms (that is, feedback activation) results in upregulation of the Ras–Raf–MEK5–ERK5 module, which maintains cell proliferation under physiological conditions, or results in continued tumour cell proliferation in colorectal cancer, respectively. However, the lack of activation of ERK1/2-specific targets results in differentiation and migration defects of intestinal epithelial cells culminating in malabsorption, wasting disease and mortality. Compensatory upregulation of the ERK5 pathway in CRC can be reversed by targeted treatment with its specific inhibitor, XMD8-92.

An unexpected finding was the redundancy of ERK1/2 in the gut with regard to cell proliferation.Erk1/2 deletion was compensated by upregulated ERK5 signalling. Genetic targeting of ERK1/2 in vitro previously showed that Erk2 knockdown is more effective than Erk1 knockdown in suppressing cell proliferation, although this may be related to higher expression levels of the former39. The effect of gene dosage was demonstrated in vivo by the observations that whileErk1−/− mice are viable12 and Erk2−/− mice die in utero13, Erk2+/− mice are only viable when at least one copy of Erk1 is present. However, mice heterozygous (+/−) for both Erk1 and Erk2 alleles were born at lower than Mendelian ratio39. More recently, it was reported that transgenic expression of ERK1 can compensate for Erk2 deletion40, demonstrating functional redundancy between both family members. Deletion of Erk1/2 in adult skin tissue resulted in hypoplasia, which was associated with G2/M cell cycle arrest, without notable differentiation defects of keratinocytes41. These data differ from our observations in the intestines, which might be explained by incomplete and transient siRNA-mediated knockdown of ERK1/2 in primary keratinocyte cultures41, compared with more efficient genomic deletion of Erk1 and Erk2 that is typically achieved by the Villin-Cre-ERT2 system14, possibly resulting in different outcomes.

Both ERK1/2 and ERK5 have been described to promote cell cycle progression, although they have different upstream signalling partners, MEK1/2 and MEK5, respectively1. Furthermore, ERK2 and ERK5 proteins share only about 66% sequence identity, and MEK5 is phosphorylated by MEKK2/3, which can also activate the p38 and JNK pathways42. The ERK5 pathway is classically activated by stress stimuli, in addition to mitogens; thus, it shares features of both the ERK1/2, and p38 and JNK pathways, respectively43. ERK5 induces expression of cyclin D1 (refs 44, 45), and suppresses expression of cyclin dependent kinase inhibitors46, thereby promoting G1/S-phase cell cycle progression. Importantly, the role of ERK5 in IEC differentiation and intestinal homeostasis is currently unknown. Knockout of Erk1/2 in IEC induced activity of ERK5, which was not detectable in naive mice (Fig. 3). These data suggest that the ERK1/2 and ERK5 modules may share proximal signalling components. Although EGFR is a likely candidate in this context19, 20, we found that abrogation of EGFR signalling did not prevent enhanced ERK5 activity upon MEK1/2 inhibition. Although it was originally suggested that ERK5 signalling is independent of Ras20, other groups established that Ras, either through physiological signalling47, or by its oncogenic activity48,49, activates the MEK5–ERK5 signalling axis. Thus, rewiring of signalling networks downstream of Ras could explain the supraphysiological activity of ERK5 upon conditional deletion of Erk1/2 in the intestines. In fact, it has been shown that ERK1/2 signalling mediates negative feedback on ERK5 activity50, possibly through transcriptional activation of dual specificity phosphatases (DUSPs)51. Alternatively, ERK1/2-induced FOS-like antigen 1 (Fra-1) may negatively regulate MEK5 (ref. 52). These data suggest that ERK5 is a default bypass route downstream of RTK-Ras and activated upon loss of ERK1/2-mediated repression, thereby ensuring the transduction of mitogenic signals to the nucleus (Fig. 7b). Consistent with this concept, we found that ERK5 inhibition induces atrophy of ΔIEC intestinal organoids (Fig. 4). In addition, important downstream transcriptional targets of ERK5 and ERK1/2 overlap, such as immediate-early gene Fra1 and oncogene c-Myc, whereas c-Fos and Egr1 were specifically induced by ERK1/2 (Fig. 6 and Supplementary Fig. 7). Specificity of ERK1/2 over ERK5 and other MAPK family members for the activation of c-Fos has been previously described53, demonstrating their differential biological output despite the shared ability to transduce potent mitogenic signals.

Our findings may be relevant for the use of MAPK inhibitors in the treatment of colorectal cancer. Although there was only a mild phenotype in the colons of ΔIEC mice under homeostatic conditions, the Ras–RAF–MEK–ERK pathway is generally upregulated in malignant cells including CRC54. Targeted therapy typically results in feedback activation of upstream players of the targeted kinase, which are then able to reactivate the same pathway or utilize bypass signalling routes55. For example, on activation, ERK1/2 phosphorylates EGFR, son of sevenless56, and Raf57, thereby terminating upstream signalling activity. Knockout of Erk1/2 eliminates this negative feedback. Our data suggest that ERK5 is a putative resistance pathway in the context of targeted treatment with MEK1/2 or ERK1/2 inhibitors (Fig. 7b). Different classes of MEK1/2 inhibitors display various modes of resistance to therapy (innate, adaptive and acquired)58. Since we have only used one MEK1/2 inhibitor (PD0325901) in our studies, it will be necessary to evaluate other classes of inhibitors in combination with ERK5 inhibitors. Importantly, while treatment with either the MEK1/2 or ERK5 inhibitor suppressed tumour growth in murine Apc−/− organoids, only the latter was able to inhibit the proliferation of Apc−/−;KRASG12V organoids (Fig. 6), which are more representative of human CRC. In line with this, suppression of ERK5 expression by forced expression of miR-143/145 inhibited intestinal adenoma formation in the ApcMin/+ model59, and activated MEK5 correlated with more invasive CRC in human60. ERK5 has been previously reported to mediate resistance to cytotoxic chemotherapy-induced apoptosis61. The highly specific and bioavailable ERK5 inhibitor, XMD8-92, has shown antitumour effects in multiple preclinical cancer models by inhibiting tumour angiogenesis, metastasis and chemo-resistance62. Furthermore, ERK5 inhibition does not induce feedback activation of upstream or parallel signalling pathways62. In conclusion, the ERK1/2 and ERK5 MAPK modules display a high degree of signalling plasticity in the intestinal epithelium, which has implications for targeted treatment of colorectal cancer.

 

Researchers Reveal Role of Transcription Factor Isoforms in Colon Diseases

http://www.genengnews.com/gen-news-highlights/researchers-reveal-role-of-transcription-factor-isoforms-in-colon-diseases/81252735/


 

 

 

 

 

 

 

 

Balance between the two isoforms, P1 and P2, of nuclear receptor HNF4a in the colonic crypt influences susceptibility to colitis and colon cancer. P1 is seen here in green. P2 is seen in red. [Poonamjot Deol, Sladek lab, UC Riverside]

Scientists at the University of California, Riverside have determined the distribution of the P1 and P2 isoforms of hepatocyte nuclear factor 4α (HNF4α) in the colons of mice. They report (“Opposing Roles of Nuclear Receptor HNF4α Isoforms in Colitis and Colitis-Associated Colon Cancer”) in eLife that maintaining a balance of P1 and P2 is crucial for reducing risk of contracting colon cancer and colitis.

What is already known in the field of cell biology is that the HNF4α transcription factor plays a key role in both diseases. HNF4α comes in two major isoforms, P1-HNF4α and P2-HNF4α (P1 and P2), but just how each isoform is involved in colitis and colon cancer is not understood.

“P1 and P2 have been conserved between mice and humans for 70 million years,” said Frances M. Sladek, Ph.D., professor of cell biology, who led the research project. “Both isoforms are important and we want to keep an appropriate balance between them in our gut by avoiding foods that would disrupt this balance and consuming foods that help preserve it. What these foods are is our next focus in the lab.”

The intestine is the only adult tissue in the body that expresses both P1 and P2. Dr. Sladek and her team have shown for the first time that these isoforms perform nonredundant functions in the intestine and are relevant to colitis and colitis-associated colon cancer.

“Our study also suggests that finding a drug to stabilize one isoform should be more effective than targeting both isoforms for treating colitis and colon cancer,” said Karthikeyani Chellappa, Ph.D., the first author of the research paper and a former postdoctoral researcher in Sladek’s lab.

Dr. Sladek explained that the colonic epithelial surface has finger-like invaginations (into the colonic wall) called colonic crypts that house stem cells at their base. These stem cells help regenerate new epithelial cells that continuously migrate up toward the surface, thus ensuring complete renewal of the intestinal lining every 3–5 days.

The researchers observed that the P1-positive cells were found in the surface lining and the top portion of the crypt (green in the accompanying image) whereas P2-positive cells were mostly in the proliferative compartment in the lower half of the crypt (the proliferation marker is red in the image.) Furthermore, when transgenic mice genetically engineered to have only either P1 or P2 were subjected to a carcinogen and, subsequently, to an irritant to stress the epithelial lining of the colon, the researchers found that the P1 mice showed fewer tumors than wild-type control mice. When treated with irritant alone, these mice were resistant to colitis. In sharp contrast, mice with only P2 showed more tumors and were much more susceptible to colitis.

The researchers explain these findings by invoking the “barrier function,”  a mucosal barrier generated by the colon’s epithelial cells that prevents bacteria in the gut from entering the body. In the case of P1 mice, this barrier function was enhanced. The P2 mice, on the other hand, showed a compromised barrier function, presumably allowing bacteria to pass through.

Next, the researchers examined genes expressed in the P1 and P2 mice. They found that resistin-like molecule (RELM)-beta, a cytokine (a signaling molecule of the immune system) expressed in the gastrointestinal tract and implicated in colitis, was expressed far more in the P2 mice than the P1 mice.

“This makes sense since a reduced barrier function means bacteria can go across the barrier, which activates RELM-beta,” Dr. Sladek said. “We also found that the P2 protein transcribes RELM-beta more effectively than the P1 protein.”

Next, Poonamjot Deol, Ph.D.,  an assistant project scientist in Dr. Slaked’s lab and the second author of the eLife study, will lead a project aimed at understanding how diet affects the distribution of P1 and P2 in the gut. She and others in the lab also plan to investigate how obesity and colitis may be linked. (Diet studies performed in Dr. Sladek’s lab in the past illustrated soybean oil’s adverse effect on obesity.)

“In the case of colitis, could soybean oil be playing a part in allowing bacteria to get across the barrier function?” Dr. Deol said. “We do not know. We know its detrimental effect on obesity. But more research needs to be done where colitis is concerned.”

Opposing roles of nuclear receptor HNF4α isoforms in colitis and colitis-associated colon cancer

 Karthikeyani Chellappa, 

HNF4α has been implicated in colitis and colon cancer in humans but the role of the different HNF4α isoforms expressed from the two different promoters (P1 and P2) active in the colon is not clear. Here, we show that P1-HNF4α is expressed primarily in the differentiated compartment of the mouse colonic crypt and P2-HNF4α in the proliferative compartment. Exon swap mice that express only P1- or only P2-HNF4α have different colonic gene expression profiles, interacting proteins, cellular migration, ion transport and epithelial barrier function. The mice also exhibit altered susceptibilities to experimental colitis (DSS) and colitis-associated colon cancer (AOM+DSS). When P2-HNF4α-only mice (which have elevated levels of the cytokine resistin-like β, RELMβ, and are extremely sensitive to DSS) are crossed with Retnlb-/- mice, they are rescued from mortality. Furthermore, P2-HNF4α binds and preferentially activates the RELMβ promoter. In summary, HNF4α isoforms perform non-redundant functions in the colon under conditions of stress, underscoring the importance of tracking them both in colitis and colon cancer.

 

Read Full Post »


FDA approves blood-based colorectal screen

Larry H. Bernstein, MD, FCAP, Curator

LPBI

 

FDA Clears First Blood-Based Colorectal Cancer Screening Test.
Lab Soft News by Bruce Friedman
https://www.linkedin.com/pulse/fda-clears-first-blood-based-colorectal-cancer-screening-joseph-colao

In the upcoming months, there surely will be an increasing number of blood-based genomic cancer tests approved by the FDA. This specific test market is just too attractive. In a recent note, I discussed some of these testing initiatives from the perspective of companion diagnostics (see: An Expanding Definition for Companion Diagnostics). This form of testing in used in collaboration with cancer therapy to select the right drug or monitor the effectiveness of drug therapy. Obviously and of equal importance are biomarkers intended for cancer screening. A recent article reported that the FDA has cleared the first blood-based screening test for colorectal cancer (see: FDA Clears First Blood-Based Colorectal Cancer Screening Test), Below is an excerpt from it:

The first blood-based colorectal cancer (CRC) screening test, Epi proColon...has been approved by the US Food and Drug Administration (FDA)….The Epi proColon test is a qualitative in vitro diagnostic test for detecting methylated Septin9 DNA, which has been associated with the occurrence of CRC, in plasma obtained from whole-blood specimens. It is indicated for use in average-risk patients who have chosen not to undergo other screening methods, such as colonoscopy or stool-based tests.The test was recommended for FDA approval in 2014 by the Molecular and Clinical Genetics Panel of the FDA’s Medical Devices Advisory Committee, but some of the experts were not convinced….The agency approved the Epi proColon test for CRC screening in average-risk patients (as defined by current screening guidelines) who choose not to be screened by colonoscopy or a stool-based FIT [fecal immunochemical test for occult blood in the stool].The Epi proColon blood test for CRC screening can be performed during routine office visits. It requires no dietary restrictions or alterations in medication use. The blood sample is analyzed by a local or regional diagnostic laboratory….The company will initiate a postapproval study to show the long-term benefit of blood-based CRC screening using Epi proColon, as required by the FDA.

Here’s more information about Septin9 DNA (see: Plasma methylated septin 9: a colorectal cancer screening marker):

The biomarker septin 9 has been found to be hypermethylated in nearly 100% of tissue neoplasia specimens and detected in circulating DNA fractions of CRC patients. A commercially available assay for septin 9 has been developed with moderate sensitivity (∼70%) and specificity (∼90%) and a second generation assay, Epi proColon 2.0 (Epigenomics AG), shows increased sensitivity (∼92%).The performance of the assay proved to be independent of tumor site and reaches a high sensitivity of 77%, even in early cancer stages (I and II). Furthermore, septin 9 was recently used in follow-up studies for detection of early recurrence of CRC. 

There is clearly a need for a blood-based biomarker for colorectal cancer screening. Patients tend to dislike the home stool collection that is required for fecal immunochemical tests for occult blood in the stool (FIT). Moreover, testing for blood in the stool offers a somewhat crude substitute for the identification of reliable cancer biomarkers in the blood. It must be noted, however, that some of the FDA experts in 2014 were not convinced that the septic 9 biomarker offered advantages over FIT.

I am not sure that septin 9 will be the final and most efficient biomarker for CRC but I am sure of two things. The first is that there will eventually be a high-specificity, high-sensitivity blood test for CRC. The second is that probably tens of billions of dollars would be saved by the elimination of screening colonoscopies for CRC by such a test. I found an article dating way back to 2002 about the number of screening endoscopies performed in the U.S. but the numbers are sill impressive  (see: How many endoscopies are performed for colorectal cancer screening?) Here is a quote from it: “Approximately 2.8 million flexible sigmoidoscopes and 14.2 million colonoscopies were estimated to have been performed in 2002.” Needless to say, many gastroenterologists and radiologists may be hoping that such a lab test does not reach the market soon.

Septin-9 is a protein that in humans is encoded by the SEPT9 gene.[1][2][3

SEPT9 has been shown to interact with SEPT2[4] and SEPT7.[4]

Along with AHNAK, eIF4E and S100A11, SEPT9 has been shown to be essential for pseudopod protrusion, tumor cell migration and invasion.[5]

The v2 region of the SEPT9 promoter has been shown to be methylated in colorectal cancer tissue compared with normal colonic mucosa.[6] Using highly sensitive real time PCR assays, methylated SEPT9 was detected in the blood of colorectal cancer patients. This alternate methylation pattern in cancer samples is suggestive of an aberrant activation or repression of the gene compared to normal tissue samples.[7][8]

Read Full Post »


Colon cancer and organoids

Larry H. Bernstein, MD, FCAP, Curator

LPBI

 

 

 

Guts and Glory

An open mind and collaborative spirit have taken Hans Clevers on a journey from medicine to developmental biology, gastroenterology, cancer, and stem cells.

By Anna Azvolinsky    http://www.the-scientist.com/?articles.view/articleNo/45580/title/Guts-and-Glory

Ihave had to talk a lot about my science recently and it’s made me think about how science works,” says Hans Clevers. “Scientists are trained to think science is driven by hypotheses, but for [my lab], hypothesis-driven research has never worked. Instead, it has been about trying to be as open-minded as possible—which is not natural for our brains,” adds the Utrecht University molecular genetics professor. “The human mind is such that it tries to prove it’s right, so pursuing a hypothesis can result in disaster. My advice to my own team and others is to not preformulate an answer to a scientific question, but just observe and never be afraid of the unknown. What has worked well for us is to keep an open mind and do the experiments. And find a collaborator if it is outside our niche.”

“One thing I have learned is that hypothesis-driven research tends not to be productive when you are in an unknown territory.”

Clevers entered medical school at Utrecht University in The Netherlands in 1978 while simultaneously pursuing a master’s degree in biology. Drawn to working with people in the clinic, Clevers had a training position in pediatrics lined up after medical school, but then mentors persuaded him to spend an additional year converting the master’s degree to a PhD in immunology. “At the end of that year, looking back, I got more satisfaction from the research than from seeing patients.” Clevers also had an aptitude for benchwork, publishing four papers from his PhD year. “They were all projects I had made up myself. The department didn’t do the kind of research I was doing,” he says. “Now that I look back, it’s surprising that an inexperienced PhD student could come up with a project and publish independently.”

Clevers studied T- and B-cell signaling; he set up assays to visualize calcium ion flux and demonstrated that the ions act as messengers to activate human B cells, signaling through antibodies on the cell surface. “As soon as the experiment worked, I got T cells from the lab next door and did the same experiment. That was my strategy: as soon as something worked, I would apply it elsewhere and didn’t stop just because I was a B-cell biologist and not a T-cell biologist. What I learned then, that I have continued to benefit from, is that a lot of scientists tend to adhere to a niche. They cling to these niches and are not that flexible. You think scientists are, but really most are not.”

Here, Clevers talks about promoting a collaborative spirit in research, the art of doing a pilot experiment, and growing miniature organs in a dish.

Clevers Creates

Re-search? Clevers was born in Eindhoven, in the south of The Netherlands. The town was headquarters to Philips Electronics, where his father worked as a businessman, and his mother took care of Clevers and his three brothers. Clevers did well in school but his passion was sports, especially tennis and field hockey, “a big thing in Holland.” Then in 1975, at age 18, he moved to Utrecht University, where he entered an intensive, biology-focused program. “I knew I wanted to be a biology researcher since I was young. In Dutch, the word for research is ‘onderzoek’ and I knew the English word ‘research’ and had wondered why there was the ‘re’ in the word, because I wanted to search but I didn’t want to do re-search—to find what someone else had already found.”

Opportunity to travel. “I was very disappointed in my biology studies, which were old-fashioned and descriptive,” says Clevers. He thought medicine might be more interesting and enrolled in medical school while still pursuing a master’s degree in biology at Utrecht. For the master’s, Clevers had to do three rotations. He spent a year at the International Laboratory for Research on Animal Diseases (ILRAD) in Nairobi, Kenya, and six months in Bethesda, Maryland, at the National Institutes of Health. “Holland is really small, so everyone travels.” Clevers saw those two rotations more as travel explorations. In Nairobi, he went on safaris and explored the country in Land Rovers borrowed from the institute. While in Maryland in 1980, Clevers—with the consent of his advisor, who thought it was a good idea for him to get a feel for the U.S.—flew to Portland, Oregon, and drove back to Boston with a musician friend along the Canadian border. He met the fiancé of political activist and academic Angela Davis in New York City and even stayed in their empty apartment there.

Life and lab lessons. Back in Holland, Clevers joined Rudolf Eugène Ballieux’s lab at Utrecht University to pursue his PhD, for which he studied immune cell signaling. “I didn’t learn much science from him, but I learned that you always have to create trust and to trust people around you. This became a major theme in my own lab. We don’t distrust journals or reviewers or collaborators. We trust everyone and we share. There will be people who take advantage, but there have only been a few of those. So I learned from Ballieux to give everyone maximum trust and then change this strategy only if they fail that trust. We collaborate easily because we give out everything and we also easily get reagents and tools that we may need. It’s been valuable to me in my career. And it is fun!”

Clevers Concentrates

On a mission. “Once I decided to become a scientist, I knew I needed to train seriously. Up to that point, I was totally self-trained.” From an extensive reading of the immunology literature, Clevers became interested in how T cells recognize antigens, and headed off to spend a postdoc studying the problem in Cox Terhorst’s lab at Dana-Farber Cancer Institute in Boston. “Immunology was young, but it was very exciting and there was a lot to discover. I became a professional scientist there and experienced how tough science is.” In 1988, Clevers cloned and characterized the gene for a component of the T-cell receptor (TCR) called CD3-epsilon, which binds antigen and activates intracellular signaling pathways.

On the fast track in Holland. Clevers returned to Utrecht University in 1989 as a professor of immunology. Within one month of setting up his lab, he had two graduate students and a technician, and the lab had cloned the first T cell–specific transcription factor, which they called TCF-1, in human T cells. When his former thesis advisor retired, Clevers was asked, at age 33, to become head of the immunology department. While the appointment was high-risk for him and for the department, Clevers says, he was chosen because he was good at multitasking and because he got along well with everyone.

Problem-solving strategy. “My strategy in research has always been opportunistic. One thing I have learned is that hypothesis-driven research tends not to be productive when you are in an unknown territory. I think there is an art to doing pilot experiments. So we have always just set up systems in which something happens and then you try and try things until a pattern appears and maybe you formulate a small hypothesis. But as soon as it turns out not to be exactly right, you abandon it. It’s a very open-minded type of research where you question whether what you are seeing is a real phenomenon without spending a year on doing all of the proper controls.”

Trial and error. Clevers’s lab found that while TCF-1 bound to DNA, it did not alter gene expression, despite the researchers’ tinkering with promoter and enhancer assays. “For about five years this was a problem. My first PhD students were leaving and they thought the whole TCF project was a failure,” says Clevers. His lab meanwhile cloned TCF homologs from several model organisms and made many reagents including antibodies against these homologs. To try to figure out the function of TCF-1, the lab performed a two-hybrid screen and identified components of the Wnt signaling pathway as binding partners of TCF-1. “We started to read about Wnt and realized that you study Wnt not in T cells but in frogs and flies, so we rapidly transformed into a developmental biology lab. We showed that we held the key for a major issue in developmental biology, the final protein in the Wnt cascade: TCF-1 binds b-catenin when b-catenin becomes available and activates transcription.” In 1996, Clevers published the mechanism of how the TCF-1 homolog in Xenopus embryos, called XTcf-3, is integrated into the Wnt signaling pathway.

Clevers Catapults

COURTESY OF HANS CLEVERS AND JEROEN HUIJBEN, NYMUS

3DCrypt building and colon cancer.

Clevers next collaborated with Bert Vogelstein’s lab at Johns Hopkins, linking TCF to Wnt signaling in colon cancer. In colon cancer cell lines with mutated forms of the tumor suppressor gene APC, the APC protein can’t rein in b-catenin, which accumulates in the cytoplasm, forms a complex with TCF-4 (later renamed TCF7L2) in the nucleus, and caninitiate colon cancer by changing gene expression. Then, the lab showed that Wnt signaling is necessary for self-renewal of adult stem cells, as mice missing TCF-4 do not have intestinal crypts, the site in the gut where stem cells reside. “This was the first time Wnt was shown to play a role in adults, not just during development, and to be crucial for adult stem cell maintenance,” says Clevers. “Then, when I started thinking about studying the gut, I realized it was by far the best way to study stem cells. And I also realized that almost no one in the world was studying the healthy gut. Almost everyone who researched the gut was studying a disease.” The main advantages of the murine model are rapid cell turnover and the presence of millions of stereotypic crypts throughout the entire intestine.

Against the grain. In 2007, Nick Barker, a senior scientist in the Clevers lab, identified the Wnt target gene Lgr5 as a unique marker of adult stem cells in several epithelial organs, including the intestine, hair follicle, and stomach. In the intestine, the gene codes for a plasma membrane protein on crypt stem cells that enable the intestinal epithelium to self-renew, but can also give rise to adenomas of the gut. Upon making mice with adult stem cell populations tagged with a fluorescent Lgr5-binding marker, the lab helped to overturn assumptions that “stem cells are rare, impossible to find, quiescent, and divide asymmetrically.”

On to organoids. Once the lab could identify adult stem cells within the crypts of the gut, postdoc Toshiro Sato discovered that a single stem cell, in the presence of Matrigel and just three growth factors, could generate a miniature crypt structure—what is now called an organoid. “Toshi is very Japanese and doesn’t always talk much,” says Clevers. “One day I had asked him, while he was at the microscope, if the gut stem cells were growing, and he said, ‘Yes.’ Then I looked under the microscope and saw the beautiful structures and said, ‘Why didn’t you tell me?’ and he said, ‘You didn’t ask.’ For three months he had been growing them!” The lab has since also grown mini-pancreases, -livers, -stomachs, and many other mini-organs.

Tumor Organoids. Clevers showed that organoids can be grown from diseased patients’ samples, a technique that could be used in the future to screen drugs. The lab is also building biobanks of organoidsderived from tumor samples and adjacent normal tissue, which could be especially useful for monitoring responses to chemotherapies. “It’s a similar approach to getting a bacterium cultured to identify which antibiotic to take. The most basic goal is not to give a toxic chemotherapy to a patient who will not respond anyway,” says Clevers. “Tumor organoids grow slower than healthy organoids, which seems counterintuitive, but with cancer cells, often they try to divide and often things go wrong because they don’t have normal numbers of chromosomes and [have] lots of mutations. So, I am not yet convinced that this approach will work for every patient. Sometimes, the tumor organoids may just grow too slowly.”

Selective memory. “When I received the Breakthrough Prize in 2013, I invited everyone who has ever worked with me to Amsterdam, about 100 people, and the lab organized a symposium where many of the researchers gave an account of what they had done in the lab,” says Clevers. “In my experience, my lab has been a straight line from cloning TCF-1 to where we are now. But when you hear them talk it was ‘Hans told me to try this and stop this’ and ‘Half of our knockout mice were never published,’ and I realized that the lab is an endless list of failures,” Clevers recalls. “The one thing we did well is that we would start something and, as soon as it didn’t look very good, we would stop it and try something else. And the few times when we seemed to hit gold, I would regroup my entire lab. We just tried a lot of things, and the 10 percent of what worked, those are the things I remember.”

Greatest Hits

  • Cloned the first T cell–specific transcription factor, TCF-1, and identified homologous genes in model organisms including the fruit fly, frog, and worm
  • Found that transcriptional activation by the abundant β-catenin/TCF-4 [TCF7L2] complex drives cancer initiation in colon cells missing the tumor suppressor protein APC
  • First to extend the role of Wnt signaling from developmental biology to adult stem cells by showing that the two Wnt pathway transcription factors, TCF-1 and TCF-4, are necessary for maintaining the stem cell compartments in the thymus and in the crypt structures of the small intestine, respectively
  • Identified Lgr5 as an adult stem cell marker of many epithelial stem cells including those of the colon, small intestine, hair follicle, and stomach, and found that Lgr5-expressing crypt cells in the small intestine divide constantly and symmetrically, disproving the common belief that stem cell division is asymmetrical and uncommon
  • Established a three-dimensional, stable model, the “organoid,” grown from adult stem cells, to study diseased patients’ tissues from the gut, stomach, liver, and prostate
 Regenerative Medicine Comes of Age   
“Anti-Aging Medicine” Sounds Vaguely Disreputable, So Serious Scientists Prefer to Speak of “Regenerative Medicine”
  • Induced pluripotent stem cells (iPSCs) and genome-editing techniques have facilitated manipulation of living organisms in innumerable ways at the cellular and genetic levels, respectively, and will underpin many aspects of regenerative medicine as it continues to evolve.

    An attitudinal change is also occurring. Experts in regenerative medicine have increasingly begun to embrace the view that comprehensively repairing the damage of aging is a practical and feasible goal.

    A notable proponent of this view is Aubrey de Grey, Ph.D., a biomedical gerontologist who has pioneered an regenerative medicine approach called Strategies for Engineered Negligible Senescence (SENS). He works to “develop, promote, and ensure widespread access to regenerative medicine solutions to the disabilities and diseases of aging” as CSO and co-founder of the SENS Research Foundation. He is also the editor-in-chief of Rejuvenation Research, published by Mary Ann Liebert.

    Dr. de Grey points out that stem cell treatments for age-related conditions such as Parkinson’s are already in clinical trials, and immune therapies to remove molecular waste products in the extracellular space, such as amyloid in Alzheimer’s, have succeeded in such trials. Recently, there has been progress in animal models in removing toxic cells that the body is failing to kill. The most encouraging work is in cancer immunotherapy, which is rapidly advancing after decades in the doldrums.

    Many damage-repair strategies are at an  early stage of research. Although these strategies look promising, they are handicapped by a lack of funding. If that does not change soon, the scientific community is at risk of failing to capitalize on the relevant technological advances.

    Regenerative medicine has moved beyond boutique applications. In degenerative disease, cells lose their function or suffer elimination because they harbor genetic defects. iPSC therapies have the potential to be curative, replacing the defective cells and eliminating symptoms in their entirety. One of the biggest hurdles to commercialization of iPSC therapies is manufacturing.

  • Building Stem Cell Factories

    Cellular Dynamics International (CDI) has been developing clinically compatible induced pluripotent stem cells (iPSCs) and iPSC-derived human retinal pigment epithelial (RPE) cells. CDI’s MyCell Retinal Pigment Epithelial Cells are part of a possible therapy for macular degeneration. They can be grown on bioengineered, nanofibrous scaffolds, and then the RPE cell–enriched scaffolds can be transplanted into patients’ eyes. In this pseudo-colored image, RPE cells are shown growing over the nanofibers. Each cell has thousands of “tongue” and “rod” protrusions that could naturally support rod and cone cells in the eye.

    “Now that an infrastructure is being developed to make unlimited cells for the tools business, new opportunities are being created. These cells can be employed in a therapeutic context, and they can be used to understand the efficacy and safety of drugs,” asserts Chris Parker, executive vice president and CBO, Cellular Dynamics International (CDI). “CDI has the capability to make a lot of cells from a single iPSC line that represents one person (a capability termed scale-up) as well as the capability to do it in parallel for multiple individuals (a capability termed scale-out).”

    Minimally manipulated adult stem cells have progressed relatively quickly to the clinic. In this scenario, cells are taken out of the body, expanded unchanged, then reintroduced. More preclinical rigor applies to potential iPSC therapy. In this case, hematopoietic blood cells are used to make stem cells, which are manufactured into the cell type of interest before reintroduction. Preclinical tests must demonstrate that iPSC-derived cells perform as intended, are safe, and possess little or no off-target activity.

    For example, CDI developed a Parkinsonian model in which iPSC-derived dopaminergic neurons were introduced to primates. The model showed engraftment and enervation, and it appeared to be free of proliferative stem cells.

    • “You will see iPSCs first used in clinical trials as a surrogate to understand efficacy and safety,” notes Mr. Parker. “In an ongoing drug-repurposing trial with GlaxoSmithKline and Harvard University, iPSC-derived motor neurons will be produced from patients with amyotrophic lateral sclerosis and tested in parallel with the drug.” CDI has three cell-therapy programs in their commercialization pipeline focusing on macular degeneration, Parkinson’s disease, and postmyocardial infarction.

    • Keeping an Eye on Aging Eyes

      The California Project to Cure Blindness is evaluating a stem cell–based treatment strategy for age-related macular degeneration. The strategy involves growing retinal pigment epithelium (RPE) cells on a biostable, synthetic scaffold, then implanting the RPE cell–enriched scaffold to replace RPE cells that are dying or dysfunctional. One of the project’s directors, Dennis Clegg, Ph.D., a researcher at the University of California, Santa Barbara, provided this image, which shows stem cell–derived RPE cells. Cell borders are green, and nuclei are red.

      The eye has multiple advantages over other organ systems for regenerative medicine. Advanced surgical methods can access the back of the eye, noninvasive imaging methods can follow the transplanted cells, good outcome parameters exist, and relatively few cells are needed.

      These advantages have attracted many groups to tackle ocular disease, in particular age-related macular degeneration, the leading cause of blindness in the elderly in the United States. Most cases of age-related macular degeneration are thought to be due to the death or dysfunction of cells in the retinal pigment epithelium (RPE). RPE cells are crucial support cells for the rods, cones, and photoreceptors. When RPE cells stop working or die, the photoreceptors die and a vision deficit results.

      A regenerated and restored RPE might prevent the irreversible loss of photoreceptors, possibly via the the transplantation of functionally polarized RPE monolayers derived from human embryonic stem cells. This approach is being explored by the California Project to Cure Blindness, a collaborative effort involving the University of Southern California (USC), the University of California, Santa Barbara (UCSB), the California Institute of Technology, City of Hope, and Regenerative Patch Technologies.

      The project, which is funded by the California Institute of Regenerative Medicine (CIRM), started in 2010, and an IND was filed early 2015. Clinical trial recruitment has begun.

      One of the project’s leaders is Dennis Clegg, Ph.D., Wilcox Family Chair in BioMedicine, UCSB. His laboratory developed the protocol to turn undifferentiated H9 embryonic stem cells into a homogenous population of RPE cells.

      “These are not easy experiments,” remarks Dr. Clegg. “Figuring out the biology and how to make the cell of interest is a challenge that everyone in regenerative medicine faces. About 100,000 RPE cells will be grown as a sheet on a 3 × 5 mm biostable, synthetic scaffold, and then implanted in the patients to replace the cells that are dying or dysfunctional. The idea is to preserve the photoreceptors and to halt disease progression.”

      Moving therapies such as this RPE treatment from concept to clinic is a huge team effort and requires various kinds of expertise. Besides benefitting from Dr. Clegg’s contribution, the RPE project incorporates the work of Mark Humayun, M.D., Ph.D., co-director of the USC Eye Institute and director of the USC Institute for Biomedical Therapeutics and recipient of the National Medal of Technology and Innovation, and David Hinton, Ph.D., a researcher at USC who has studied how actvated RPE cells can alter the local retinal microenvironment.

Read Full Post »


Microbe meets cancer

Larry H. Bernstein, MD, FCAP, Curator

LPBI

 

Microbes Meet Cancer

Understanding cancer’s relationship with the human microbiome could transform immune-modulating therapies.

By Kate Yandell | April 1, 2016  http://www.the-scientist.com/?articles.view/articleNo/45616/title/Microbes-Meet-Cancer

 © ISTOCK.COM/KATEJA_FN; © ISTOCK.COM/FRANK RAMSPOTT  http://www.the-scientist.com/images/April2016/feature1.jpg

In 2013, two independent teams of scientists, one in Maryland and one in France, made a surprising observation: both germ-free mice and mice treated with a heavy dose of antibiotics responded poorly to a variety of cancer therapies typically effective in rodents. The Maryland team, led by Romina Goldszmidand Giorgio Trinchieri of the National Cancer Institute, showed that both an investigational immunotherapy and an approved platinum chemotherapy shrank a variety of implanted tumor types and improved survival to a far greater extent in mice with intact microbiomes.1 The French group, led by INSERM’s Laurence Zitvogel, got similar results when testing the long-standing chemotherapeutic agent cyclophosphamide in cancer-implanted mice, as well as in mice genetically engineered to develop tumors of the lung.2

The findings incited a flurry of research and speculation about how gut microbes contribute to cancer cell death, even in tumors far from the gastrointestinal tract. The most logical link between the microbiome and cancer is the immune system. Resident microbes can either dial up inflammation or tamp it down, and can modulate immune cells’ vigilance for invaders. Not only does the immune system appear to be at the root of how the microbiome interacts with cancer therapies, it also appears to mediate how our bacteria, fungi, and viruses influence cancer development in the first place.

“We clearly see shifts in the [microbial] community that precede development of tumors,” says microbiologist and immunologist Patrick Schloss, who studies the influence of the microbiome on colon cancer at the University of Michigan.

But the relationship between the microbiome and cancer is complex: while some microbes promote cell proliferation, others appear to protect us against cancerous growth. And in some cases, the conditions that spur one cancer may have the opposite effect in another. “It’s become pretty obvious that the commensal microbiota affect inflammation and, through that or through other mechanisms, affect carcinogenesis,” says Trinchieri. “What we really need is to have a much better understanding of which species, which type of bug, is doing what and try to change the balance.”

Gut feeling

In the late 1970s, pathologist J. Robin Warren of Royal Perth Hospital in Western Australia began to notice that curved bacteria often appeared in stomach tissue biopsies taken from patients with chronic gastritis, an inflammation of the stomach lining that often precedes the development of stomach cancer. He and Barry J. Marshall, a trainee in internal medicine at the hospital, speculated that the bacterium, now called Helicobacter pylori, was somehow causing the gastritis.3 So committed was Marshall to demonstrating the microbe’s causal relationship to the inflammatory condition that he had his own stomach biopsied to show that it contained no H. pylori, then infected himself with the bacterium and documented his subsequent experience of gastritis.4 Scientists now accept that H. pylori, a common gut microbe that is present in about 50 percent of the world’s population, is responsible for many cases of gastritis and most stomach ulcers, and is a strong risk factor for stomach cancer.5 Marshall and Warren earned the 2005 Nobel Prize in Physiology or Medicine for their work.

H. pylori may be the most clear-cut example of a gut bacterium that influences cancer development, but it is likely not the only one. Researchers who study cancer in mice have long had anecdotal evidence that shifts in the microbiome influence the development of diverse tumor types. “You have a mouse model of carcinogenesis. It works beautifully,” says Trinchieri. “You move to another institution. It works completely differently,” likely because the animals’ microbiomes vary with environment.

IMMUNE INFLUENCE: In recent years, research has demonstrated that microbes living in and on the mammalian body can affect cancer risk, as well as responses to cancer treatment. Although the details of this microbe-cancer link remain unclear, investigators suspect that the microbiome’s ability to modulate inflammation and train immune cells to react to tumors is to blame.
See full infographic: WEB | PDF
© AL GRANBERG

Around the turn of the 21st century, cancer researchers began to systematically experiment with the rodent microbiome, and soon had several lines of evidence linking certain gut microbes with a mouse’s risk of colon cancer. In 2001, for example, Shoichi Kado of the Yakult Central Institute for Microbiological Research in Japan and colleagues found that a strain of immunocompromised mice rapidly developed colon tumors, but that germ-free versions of these mice did not.6 That same year, an MIT-based group led by the late David Schauer demonstrated that infecting mice with the bacterium Citrobacter rodentium spurred colon tumor development.7 And in 2003, MIT’s Susan Erdman and her colleagues found that they could induce colon cancer in immunocompromised mice by infecting them with Helicobacter hepaticus, a relative of? H. pylori that commonly exists within the murine gut microbiome.8

More recent work has documented a similar link between colon cancer and the gut microbiome in humans. In 2014, a team led by Schloss sequenced 16S rRNA genes isolated from the stool of 90 people, some with colon cancer, some with precancerous adenomas, and still others with no disease.9 The researchers found that the feces of people with cancer tended to have an altered composition of bacteria, with an excess of the common mouth microbes Fusobacterium or Porphyromonas. A few months later, Peer Bork of the European Molecular Biology Laboratory performed metagenomic sequencing of stool samples from 156 people with or without colorectal cancer. Bork and his colleagues found they could predict the presence or absence of cancer using the relative abundance of 22 bacterial species, including Porphyromonas andFusobacterium.10 They could also use the method to predict colorectal cancer with about the same accuracy as a blood test, correctly identifying about 50 percent of cancers while yielding false positives less than 10 percent of the time. When the two tests were combined, they caught more than 70 percent of cancers.

Whether changes in the microbiota in colon cancer patients are harbingers of the disease or a consequence of tumor development remained unclear. “What comes first, the change in the microbiome or tumor development?” asks Schloss. To investigate this question, he and his colleagues treated mice with microbiome-altering antibiotics before administering a carcinogen and an inflammatory agent, then compared the outcomes in those animals and in mice that had received only the carcinogenic and inflammatory treatments, no antibiotics. The antibiotic-treated animals had significantly fewer and smaller colon tumors than the animals with an undisturbed microbiome, suggesting that resident bacteria were in some way promoting cancer development. And when the researchers transferred microbiota from healthy mice to antibiotic-treated or germ-free mice, the animals developed more tumors following carcinogen exposure. Sterile mice that received microbiota from mice already bearing malignancies developed the most tumors of all.11

Most recently, Schloss and his colleagues showed that treating mice with seven unique combinations of antibiotics prior to exposing them to carcinogens yielded variable but predictable levels of tumor formation. The researchers determined that the number of tumors corresponded to the unique ways that each antibiotic cocktail modulated the microbiome.12

“We’ve kind of proven to ourselves, at least, that the microbiome is involved in colon cancer,” says Schloss, who hypothesizes that gut bacteria–driven inflammation is to blame for creating an environment that is hospitable to tumor development and growth. Gain or loss of certain components of the resident bacterial community could lead to the release of reactive oxygen species, damaging cells and their genetic material. Inflammation also involves increased release of growth factors and blood vessel proliferation, potentially supporting the growth of tumors. (See illustration above.)

Recent research has also yielded evidence that the gut microbiota impact the development of cancer in sites far removed from the intestinal tract, likely through similar immune-modulating mechanisms.

Systemic effects

In the mid-2000s, MIT’s Erdman began infecting a strain of mice predisposed to intestinal tumors withH. hepaticus and observing the subsequent development of colon cancer in some of the animals. To her surprise, one of the mice developed a mammary tumor. Then, more of the mice went on to develop mammary tumors. “This told us that something really interesting was going on,” Erdman recalls. Sure enough, she and her colleagues found that mice infected with H. hepaticus were more likely to develop mammary tumors than mice not exposed to the bacterium.13The researchers showed that systemic immune activation and inflammation could contribute to mammary tumors in other, less cancer-prone mouse models, as well as to the development of prostate cancer.

MICROBIAL STOWAWAYS: Bacteria of the human gut microbiome are intimately involved in cancer development and progression, thanks to their interactions with the immune system. Some microbes, such as Helicobacter pylori, increase the risk of cancer in their immediate vicinity (stomach), while others, such as some Bacteroides species, help protect against tumors by boosting T-cell infiltration.© EYE OF SCIENCE/SCIENCE SOURCE
http://www.the-scientist.com/images/April2016/immune_2.jpg

 

 

© DR. GARY GAUGLER/SCIENCE SOURCE  http://www.the-scientist.com/images/April2016/immune3.jpg

At the University of Chicago, Thomas Gajewski and his colleagues have taken a slightly different approach to studying the role of the microbiome in cancer development. By comparing Black 6 mice coming from different vendors—Taconic Biosciences (formerly Taconic Farms) and the Jackson Laboratory—Gajewski takes advantage of the fact that the animals’ different origins result in different gut microbiomes. “We deliberately stayed away from antibiotics, because we had a desire to model how intersubject heterogeneity [in cancer development] might be impacted by the commensals they happen to be colonized with,” says Gajewski in an email to The Scientist.

Last year, the researchers published the results of a study comparing the progression of melanoma tumors implanted under the mice’s skin, finding that tumors in the Taconic mice grew more aggressively than those in the Jackson mice. When the researchers housed the different types of mice together before their tumors were implanted, however, these differences disappeared. And transferring fecal material from the Jackson mice into the Taconic mice altered the latter’s tumor progression.14

Instead of promoting cancer, in these experiments the gut microbiome appeared to slow tumor growth. Specifically, the reduced tumor growth in the Jackson mice correlated with the presence of Bifidobacterium, which led to the greater buildup of T?cells in the Jackson mice’s tumors. Bifidobacteriaactivate dendritic cells, which present antigens from bacteria or cancer cells to T?cells, training them to hunt down and kill these invaders. Feeding Taconic mice bifidobacteria improved their response to the implanted melanoma cells.

“One hypothesis going into the experiments was that we might identify immune-suppressive bacteria, or commensals that shift the immune response towards a character that was unfavorable for tumor control,” says Gajewski.  “But in fact, we found that even a single type of bacteria could boost the antitumor immune response.”

http://www.the-scientist.com/images/April2016/immune4.jpg

 

Drug interactions

Ideally, the immune system should recognize cancer as invasive and nip tumor growth in the bud. But cancer cells display “self” molecules that can inhibit immune attack. A new type of immunotherapy, dubbed checkpoint inhibition or blockade, spurs the immune system to attack cancer by blocking either the tumor cells’ surface molecules or the receptors on T?cells that bind to them.

CANCER THERAPY AND THE MICROBIOME

In addition to influencing the development and progression of cancer by regulating inflammation and other immune pathways, resident gut bacteria appear to influence the effectiveness of many cancer therapies that are intended to work in concert with host immunity to eliminate tumors.

  • Some cancer drugs, such as oxaliplatin chemotherapy and CpG-oligonucleotide immunotherapy, work by boosting inflammation. If the microbiome is altered in such a way that inflammation is reduced, these therapeutic agents are less effective.
  • Cancer-cell surface proteins bind to receptors on T cells to prevent them from killing cancer cells. Checkpoint inhibitors that block this binding of activated T cells to cancer cells are influenced by members of the microbiota that mediate these same cell interactions.
  • Cyclophosphamide chemotherapy disrupts the gut epithelial barrier, causing the gut to leak certain bacteria. Bacteria gather in lymphoid tissue just outside the gut and spur generation of T helper 1 and T helper 17 cells that migrate to the tumor and kill it.

As part of their comparison of Jackson and Taconic mice, Gajewski and his colleagues decided to test a type of investigational checkpoint inhibitor that targets PD-L1, a ligand found in high quantities on the surface of multiple types of cancer cells. Monoclonal antibodies that bind to PD-L1 block the PD-1 receptors on T?cells from doing so, allowing an immune response to proceed against the tumor cells. While treating Taconic mice with PD-L1–targeting antibodies did improve their tumor responses, they did even better when that treatment was combined with fecal transfers from Jackson mice, indicating that the microbiome and the immunotherapy can work together to take down cancer. And when the researchers combined the anti-PD-L1 therapy with a bifidobacteria-enriched diet, the mice’s tumors virtually disappeared.14

Gajewski’s group is now surveying the gut microbiota in humans undergoing therapy with checkpoint inhibitors to better understand which bacterial species are linked to positive outcomes. The researchers are also devising a clinical trial in which they will give Bifidobacterium supplements to cancer patients being treated with the approved anti-PD-1 therapy pembrolizumab (Keytruda), which targets the immune receptor PD-1 on T?cells, instead of the cancer-cell ligand PD-L1.

Meanwhile, Zitvogel’s group at INSERM is investigating interactions between the microbiome and another class of checkpoint inhibitors called CTLA-4 inhibitors, which includes the breakthrough melanoma treatment ipilimumab (Yervoy). The researchers found that tumors in antibiotic-treated and germ-free mice had poorer responses to a CTLA-4–targeting antibody compared with mice harboring unaltered microbiomes.15 Particular Bacteroides species were associated with T-cell infiltration of tumors, and feedingBacteroides fragilis to antibiotic-treated or germ-free mice improved the animals’ responses to the immunotherapy. As an added bonus, treatment with these “immunogenic” Bacteroides species decreased signs of colitis, an intestinal inflammatory condition that is a dangerous side effect in patients using checkpoint inhibitors. Moreover, Zitvogel and her colleagues showed that human metastatic melanoma patients treated with ipilimumab tended to have elevated levels of B. fragilis in their microbiomes. Mice transplanted with feces from patients who showed particularly strong B. fragilis gains did better on anti-CTLA-4 treatment than did mice transplanted with feces from patients with normal levels of B. fragilis.

“There are bugs that allow the therapy to work, and at the same time, they protect against colitis,” says Trinchieri. “That is very exciting, because not only [can] we do something to improve the therapy, but we can also, at the same time, try to reduce the side effect.”

And these checkpoint inhibitors aren’t the only cancer therapies whose effects are modulated by the microbiome. Trinchieri has also found that an immunotherapy that combines antibodies against interleukin-10 receptors with CpG oligonucleotides is more effective in mice with unaltered microbiomes.1He and his NCI colleague Goldszmid further found that the platinum chemotherapy oxaliplatin (Eloxatin) was more effective in mice with intact microbiomes, and Zitvogel’s group has shown that the chemotherapeutic agent cyclophosphamide is dependent on the microbiota for its proper function.

Although the mechanisms by which the microbiome influences the effectiveness of such therapies remains incompletely understood, researchers once again speculate that the immune system is the key link. Cyclophosphamide, for example, spurs the body to generate two types of T?helper cells, T?helper 1 cells and a subtype of T?helper 17 cells referred to as “pathogenic,” both of which destroy tumor cells. Zitvogel and her colleagues found that, in mice with unaltered microbiomes, treatment with cyclophosphamide works by disrupting the intestinal mucosa, allowing bacteria to escape into the lymphoid tissues just outside the gut. There, the bacteria spur the body to generate T?helper 1 and T?helper 17 cells, which translocate to the tumor. When the researchers transferred the “pathogenic” T?helper 17 cells into antibiotic-treated mice, the mice’s response to chemotherapy was partly restored.

Microbiome modification

As the link between the microbiome and cancer becomes clearer, researchers are thinking about how they can manipulate a patient’s resident microbial communities to improve their prognosis and treatment outcomes. “Once you figure out exactly what is happening at the molecular level, if there is something promising there, I would be shocked if people don’t then go in and try to modulate the microbiome, either by using pharmaceuticals or using probiotics,” says Michael Burns, a postdoc in the lab of University of Minnesota genomicist Ran Blekhman.

Even if researchers succeed in identifying specific, beneficial alterations to the microbiome, however, molding the microbiome is not simple. “It’s a messy, complicated system that we don’t understand,” says Schloss.

So far, studies of the gut microbiome and colon cancer have turned up few consistent differences between cancer patients and healthy controls. And the few bacterial groups that have repeatedly shown up are not present in every cancer patient. “We should move away from saying, ‘This is a causal species of bacteria,’” says Blekhman. “It’s more the function of a community instead of just a single bacterium.”

But the study of the microbiome in cancer is young. If simply adding one type of microbe into a person’s gut is not enough, researchers may learn how to dose people with patient-specific combinations of microbes or antibiotics. In February 2016, a team based in Finland and China showed that a probiotic mixture dubbed Prohep could reduce liver tumor size by 40 percent in mice, likely by promoting an anti-inflammatory environment in the gut.16

“If it is true that, in humans, we can alter the course of the disease by modulating the composition of the microbiota,” says José Conejo-Garcia of the Wistar Institute in Philadelphia, “that’s going to be very impactful.”

Kate Yandell has been a freelance writer living Philadelphia, Pennsylvania. In February she became an associate editor at Cancer Today.

GENETIC CONNECTION

The microbiome doesn’t act in isolation; a patient’s genetic background can also greatly influence response to therapy. Last year, for example, the Wistar Institute’s José Garcia-Conejo and Melanie Rutkowski, now an assistant professor at the University of Virginia, showed that a dominant polymorphism of the gene for the innate immune protein toll-like receptor 5 (TLR5) influences clinical outcomes in cancer patients by changing how the patients’ immune cells interact with their gut microbes (Cancer Cell, 27:27-40, 2015).

More than 7 percent of people carry a specific mutation in TLR5 that prevents them from mounting a full immune response when exposed to bacterial flagellin. Analyzing both genetic and survival data from the Cancer Genome Atlas, Conejo-Garcia, Rutkowski, and their colleagues found that estrogen receptor–positive breast cancer patients who carry the TLR5 mutation, called the R392X polymorphism, have worse outcomes than patients without the mutation. Among patients with ovarian cancer, on the other hand, those with the TLR5 mutation were more likely to live at least six years after diagnosis than patients who don’t carry the mutation.

Investigating the mutation’s contradictory effects, the researchers found that mice with normal TLR5produce higher levels of the cytokine interleukin 6 (IL-6) than those carrying the mutant version, which have higher levels of a different cytokine called interleukin 17 (IL-17). But when the researchers knocked out the animals’ microbiomes, these differences in cytokine production disappeared, as did the differences in cancer progression between mutant and wild-type animals.

“The effectiveness of depleting specific populations or modulating the composition of the microbiome is going to affect very differently people who are TLR5-positive or TLR5-negative,” says Conejo-Garcia. And Rutkowski speculates that many more polymorphisms linked to cancer prognosis may act via microbiome–immune system interactions. “I think that our paper is just the tip of the iceberg.”

References

  1. N. Iida et al., “Commensal bacteria control cancer response to therapy by modulating the tumor microenvironment,” Science, 342:967-70, 2013.
  2. S. Viaud et al., “The intestinal microbiota modulates the anticancer immune effects of cyclophosphamide,” Science, 342:971-76, 2013.
  3. J.R. Warren, B. Marshall, “Unidentified curved bacilli on gastric epithelium in active chronic gastritis,”Lancet, 321:1273-75, 1983.
  4. B.J. Marshall et al., “Attempt to fulfil Koch’s postulates for pyloric Campylobacter,” Med J Aust, 142:436-39, 1985.
  5. J. Parsonnet et al., “Helicobacter pylori infection and the risk of gastric carcinoma,” N Engl J Med, 325:1127-31, 1991.
  6. S. Kado et al., “Intestinal microflora are necessary for development of spontaneous adenocarcinoma of the large intestine in T-cell receptor β chain and p53 double-knockout mice,” Cancer Res, 61:2395-98, 2001.
  7. J.V. Newman et al., “Bacterial infection promotes colon tumorigenesis in ApcMin/+ mice,” J Infect Dis, 184:227-30, 2001.
  8. S.E. Erdman et al., “CD4+ CD25+ regulatory T lymphocytes inhibit microbially induced colon cancer in Rag2-deficient mice,” Am J Pathol, 162:691-702, 2003.
  9. J.P. Zackular et al., “The human gut microbiome as a screening tool for colorectal cancer,” Cancer Prev Res, 7:1112-21, 2014.
  10. G. Zeller et al., “Potential of fecal microbiota for early-stage detection of colorectal cancer,” Mol Syst Biol, 10:766, 2014.
  11. J.P. Zackular et al., “The gut microbiome modulates colon tumorigenesis,” mBio, 4:e00692-13, 2013.
  12. J.P. Zackular et al., “Manipulation of the gut microbiota reveals role in colon tumorigenesis,”mSphere, doi:10.1128/mSphere.00001-15, 2015.
  13. V.P. Rao et al., “Innate immune inflammatory response against enteric bacteria Helicobacter hepaticus induces mammary adenocarcinoma in mice,” Cancer Res, 66:7395, 2006.
  14. A. Sivan et al., “Commensal Bifidobacterium promotes antitumor immunity and facilitates anti-PD-L1 efficacy,” Science, 350:1084-89, 2015.
  15. M. Vétizou et al., “Anticancer immunotherapy by CTLA-4 blockade relies on the gut microbiota,”Science, 350:1079-84, 2015.

……..

 

Microbially Driven TLR5-Dependent Signaling Governs Distal Malignant Progression through Tumor-Promoting Inflammation

Melanie R. Rutkowski, Tom L. Stephen, Nikolaos Svoronos, …., Julia Tchou,  Gabriel A. Rabinovich, Jose R. Conejo-Garcia
Cancer cell    12 Jan 2015; Volume 27, Issue 1, p27–40  http://dx.doi.org/10.1016/j.ccell.2014.11.009
Figure thumbnail fx1
  • TLR5-dependent IL-6 mobilizes MDSCs that drive galectin-1 production by γδ T cells
  • IL-17 drives malignant progression in IL-6-unresponsive tumors
  • TLR5-dependent differences in tumor growth are abrogated upon microbiota depletion
  • A common dominant TLR5 polymorphism influences the outcome of human cancers

The dominant TLR5R392X polymorphism abrogates flagellin responses in >7% of humans. We report that TLR5-dependent commensal bacteria drive malignant progression at extramucosal locations by increasing systemic IL-6, which drives mobilization of myeloid-derived suppressor cells (MDSCs). Mechanistically, expanded granulocytic MDSCs cause γδ lymphocytes in TLR5-responsive tumors to secrete galectin-1, dampening antitumor immunity and accelerating malignant progression. In contrast, IL-17 is consistently upregulated in TLR5-unresponsive tumor-bearing mice but only accelerates malignant progression in IL-6-unresponsive tumors. Importantly, depletion of commensal bacteria abrogates TLR5-dependent differences in tumor growth. Contrasting differences in inflammatory cytokines and malignant evolution are recapitulated in TLR5-responsive/unresponsive ovarian and breast cancer patients. Therefore, inflammation, antitumor immunity, and the clinical outcome of cancer patients are influenced by a common TLR5 polymorphism.

see also… Immune Influence

In recent years, research has demonstrated that microbes living in and on the mammalian body can affect cancer risk, as well as responses to cancer treatment.

By Kate Yandell | April 1, 2016

http://www.the-scientist.com/?articles.view/articleNo/45644/title/Immune-Influence

Although the details of this microbe-cancer link remain unclear, investigators suspect that the microbiome’s ability to modulate inflammation and train immune cells to react to tumors is to blame. Here are some of the hypotheses that have come out of recent research in rodents for how gut bacteria shape immunity and influence cancer.

HOW THE MICROBIOME PROMOTES CANCER

Gut bacteria can dial up inflammation locally in the colon, as well as in other parts of the body, leading to the release of reactive oxygen species, which damage cells and DNA, and of growth factors that spur tumor growth and blood vessel formation.

http://www.the-scientist.com/images/April2016/ImmuneInfluence1_640px.jpg

http://www.the-scientist.com/images/April2016/ImmuneInfluence2_310px1.jpg

Helicobacter pylori can cause inflammation and high cell turnover in the stomach wall, which may lead to cancerous growth.

HOW THE MICROBIOME STEMS CANCER

Gut bacteria can also produce factors that lower inflammation and slow tumor growth. Some gut bacteria (e.g., Bifidobacterium)
appear to activate dendritic cells,
which present cancer-cell antigens to T cells that in turn kill the cancer cells.

http://www.the-scientist.com/images/April2016/ImmuneInfluence3_310px1.jpg

http://www.the-scientist.com/images/April2016/ImmuneInfluence4_310px1.jpg

Read the full story.

 

Read Full Post »

Older Posts »