Advertisements
Feeds:
Posts
Comments

Archive for the ‘Stem Cells for Regenerative Medicine’ Category

Immunoediting can be a constant defense in the cancer landscape


Reporter and Curator: Dr. Sudipta Saha, Ph.D.

 

There are many considerations in the cancer immunoediting landscape of defense and regulation in the cancer hallmark biology. The cancer hallmark biology in concert with key controls of the HLA compatibility affinity mechanisms are pivotal in architecting a unique patient-centric therapeutic application. Selection of random immune products including neoantigens, antigens, antibodies and other vital immune elements creates a high level of uncertainty and risk of undesirable immune reactions. Immunoediting is a constant process. The human innate and adaptive forces can either trigger favorable or unfavorable immunoediting features. Cancer is a multi-disease entity. There are multi-factorial initiators in a certain disease process. Namely, environmental exposures, viral and / or microbiome exposure disequilibrium, direct harm to DNA, poor immune adaptability, inherent risk and an individual’s own vibration rhythm in life.

 

When a human single cell is crippled (Deranged DNA) with mixed up molecular behavior that is the initiator of the problem. A once normal cell now transitioned into full threatening molecular time bomb. In the modeling and creation of a tumor it all begins with the singular molecular crisis and crippling of a normal human cell. At this point it is either chop suey (mixed bit responses) or a productive defensive and regulation response and posture of the immune system. Mixed bits of normal DNA, cancer-laden DNA, circulating tumor DNA, circulating normal cells, circulating tumor cells, circulating immune defense cells, circulating immune inflammatory cells forming a moiety of normal and a moiety of mess. The challenge is to scavenge the mess and amplify the normal.

 

Immunoediting is a primary push-button feature that is definitely required to be hit when it comes to initiating immune defenses against cancer and an adaptation in favor of regression. As mentioned before that the tumor microenvironment is a “mixed bit” moiety, which includes elements of the immune system that can defend against circulating cancer cells and tumor growth. Personalized (Precision-Based) cancer vaccines must become the primary form of treatment in this case. Current treatment regimens in conventional therapy destroy immune defenses and regulation and create more serious complications observed in tumor progression, metastasis and survival. Commonly resistance to chemotherapeutic agents is observed. These personalized treatments will be developed in concert with cancer hallmark analytics and immunocentrics affinity and selection mapping. This mapping will demonstrate molecular pathway interface and HLA compatibility and adaptation with patientcentricity.

References:

 

https://www.linkedin.com/pulse/immunoediting-cancer-landscape-john-catanzaro/

 

https://www.cell.com/cell/fulltext/S0092-8674(16)31609-9

 

https://www.researchgate.net/publication/309432057_Circulating_tumor_cell_clusters_What_we_know_and_what_we_expect_Review

 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4190561/

 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5840207/

 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5593672/

 

https://www.frontiersin.org/articles/10.3389/fimmu.2018.00414/full

 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5593672/

 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4190561/

 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4388310/

 

https://www.linkedin.com/pulse/cancer-hallmark-analytics-omics-data-pathway-studio-review-catanzaro/

 

Advertisements

Read Full Post »


Functioning Human Neural Networks Grown in 3-D from Stem Cells

Reporter: Irina Robu, PhD

 

Researchers at Tuffs University developed three-dimensional human tissue model that mimics structural and functional features of the brain and were able to demonstrate sustained neural activity over several months. The 3D brain tissue models were the result of a collaborative effort between researchers from Tufts University School of Engineering, Tufts University School of Medicine, the Sackler School of Graduate Biomedical Sciences at Tufts, and the Jackson Laboratory.

 

These tissue models have the ability to populate a 3D matrix of silk protein and collagen with cells from patients with Parkinson’s disease, Alzheimer’s disease and the ability to

  • explore cell interactions,
  • disease progression and
  • response to treatment.

The 3D brain tissue models overcome a crucial challenge of previous models which is the availability of human source neurons due to the fact that neurological tissues are rarely removed from

  • healthy patients, and are usually available
  • post-mortem from diseased patients.

The 3D tissue models are populated with human induced pluripotent stem cells (iPSCs) that can be derived from several sources, including patient skin. The iPSCs are generated by turning back the clock on cell development to their embryonic-like precursors. They can then be dialed forward again to any cell type, including neurons. The porous structure of the 3D tissue cultures labeled in the research delivers sufficient oxygenation, access for nutrients and measurement of cellular properties. A clear window in the center of each 3D matrix allows researchers to visualize the

  • growth,
  • organization and
  • behavior of individual cells.

According to David L. Kaplan, “the silk-collagen scaffolds provide the right environment to produce cells with the genetic signatures and electrical signaling found in native neuronal tissues”. Compared to growing and culturing cells in two dimensions, the three-dimensional matrix yields a knowingly extra complete mix of cells found in neural tissue, with the appropriate morphology and expression of receptors and neurotransmitters. Other researchers have used iPSCs to create brain-like organoids, but can still make it difficult figuring out what individual cells are doing in real time. Likewise, cells in the center of the organoids may not obtain enough oxygen or nutrients to function in a native state.

However, the researchers can see a great advantage of the 3D tissue models with advanced imaging techniques, and the addition of cell types such as

  • microglia and
  • endothelial cells,

to create a more complete model of the brain environment and the complex interactions that are involved in

  • signaling,
  • learning and plasticity, and
  • degeneration.

 

SOURCE

https://www.rdmag.com/news/2018/10/scientists-grow-functioning-human-neural-networks-3d-stem-cells

Read Full Post »


NHLBI decision to halt Heart Stem-Cell Study (CONCERT-HF trial) due to concerns about Anversa’s Animal Studies, not due to any Data generated by the Clinical trial itself, no compromised patient safety by trial

Reporter: Aviva Lev-Ari, PhD, RN

Doubts about Anversa’s work arose in the early 2000s after other researchers failed to replicate his findings and questioned whether cardiac stem cells existed2,3,4.

Paper of Former HMS Prof. Withdrawn, Clinical Trial Paused after Harvard Requests Retractions

https://www.thecrimson.com/article/2018/10/31/medical-school-paper-retracted/

NHLBI NEWS

Statement

Statement on NHLBI decision to pause the CONCERT-HF trial

The National Heart, Lung, and Blood Institute (NHLBI), part of the National Institutes of Health, is pausing the CONCERT-HF trialexternal link, which involves patients with chronic heart failure. Recent calls for the retraction of journal articles in related fields of cell therapy research have raised concerns about the scientific foundations of this trial.  While none of the articles in question derive from the CONCERT-HF trial itself, the NHLBI convened CONCERT-HF’s Data and Safety Monitoring Board (DSMB) out of an abundance of caution to ensure the study continues to meet the highest standards for participant safety and scientific integrity. Informed by the DSMB recommendations of October 25, 2018, the NHLBI is pausing the trial. While the DSMB did not have any participant safety concerns, this pause enables the DSMB to complete its review.

The safety of all clinical trial participants is paramount to NHLBI. NHLBI will honor its commitment to CONCERT-HF participants and continue the follow-up protocol during this pause for all participants who have already been treated in the study. Participants are being notified of the status of the trial and how to request additional information.

The CONCERT-HF trial seeks to determine whether c-kit+ cells, either alone or in combination with mesenchymal stem cells derived from the bone marrow, are safe and benefit patients with chronic heart failure, who have very limited treatment options. Despite significant medical and surgical advances, patients with heart failure continue to experience a low quality of life and about half of them will die within five years of receiving a diagnosis.

The scientific basis of CONCERT-HF is supported by a body of evidence in several preclinical models in a number of studies in a variety of laboratories and was reviewed by a Protocol Review Committee (PRC) independent of the trial. The cell therapies that CONCERT-HF is testing are under an investigational new drug (IND) designation which is overseen by the U.S. Food and Drug Administration (FDA). The cells are produced by an accredited laboratory independent of the clinical sites. In addition, as part of standard oversight of clinical trials, the DSMB routinely reviews and monitors CONCERT-HF to ensure participant safety and that the study continues to ask compelling scientific questions with implications for patient care.

The DSMB’s review will be conducted as expeditiously as possible and will inform NHLBI’s future actions that will ensure the highest standards of participant safety and scientific integrity.

SOURCE

https://www.nhlbi.nih.gov/news/2018/statement-nhlbi-decision-pause-concert-hf-trial

References

  1. Quaini, F. et al. N. Engl. J. Med. 346, 5–15 (2002).
  1. Murry, C. E. et al. Nature 428, 664–668 (2004).
  1. Balsam, L. B. Nature 428, 668–673 (2004).
  1. Nygren, J. M. et al. Nature Med. 10, 494–501 (2004).

Download references

RELATED ARTICLES

SUBJECTS

SOURCE

Read Full Post »


LIVE 2018 The 21st Gabay Award to LORENZ STUDER, Memorial Sloan Kettering Cancer Center, contributions in stem cell biology and patient-specific, cell-based therapy

REAL TIME Reporter: Aviva Lev-Ari, PhD, RN

AWARD LECTURE

Tue., Oct. 9, 2018
4:00 PM
Shapiro Campus Center Theater
Brandeis University

CURRENT WINNER

lorenzstuder.jpgLORENZ STUDER

MACARTHUR FELLOWS PROGRAM

Lorenz Studer

Stem Cell Biologist | Class of 2015

Pioneering a new method for large-scale generation of dopaminergic neurons that could provide one of the first treatments for Parkinson’s disease and prove the broader feasibility of stem cell–based therapies for other neurological disorders.

https://www.macfound.org/fellows/947/

118 publications on PubMed

https://www.ncbi.nlm.nih.gov/pubmed/?term=LORENZ+STUDER

 

PRESIDING

Dagmar Ringe Professor of Biochemistry, Chemistry and Rosenstiel Basic Medical Sciences Research Center

WELCOME

Lisa Lynch Provost and Maurice B. Hexter Professor of Social and Economic Policy Brandeis University

 

RESPONSE Lorenz Studer, MD Director, Center for Stem Cell Biology Memorial Sloan Kettering Cancer Center Member, Developmental Biology Program Memorial Sloan Kettering Cancer Center

Fully defined protocol for all ectodermal lineage

  • Nervous system: Forebrain, Midbrain, Spinal cord:
  • CNS lineage to PNS Lineage
  • Excitatory cortical neurons
  • cortical interneurons Astrocytes
  • microglia
  • Age-reset disease – late-onset during reprogramming – Is age reversible?
  • Loss of age-related markers
  • iPSC-derived cells yield stage cell upon differentiation
  • In vitro differentiation techniques: 2D Directed Differentiation 3D- Organoids
  • Graded MORPHOGEN SIGNALING
  • DOXYCYLINE: ISHH-ORGANIZER – 5 discrete forebrain regions
  • Building Human brain cells in 2D and in 3D
  • Organized cells –>>>  directed organoids –>> Organized Organoids
  • Parkinson, 1817 – Essay on Shaky Palsy (Niagrostaterial pathway)
  • Genetics and related dysfunction: affecting PD
  • Charckot, 1889
  • PD – new approach following drugs and deep brain stimulation failure in advanced disease: Fetal tissue transplant trials: Fetal Grafting
  • graft-induced dyskinesia
  • Long term, 15 years positive effects
  • Stem-cell-based regenerative therapy could transform PD therapy
  • 1995  Fetal DA neuron grafting for PD in Switzerland
  • 1998 – midbrain stem cell derived DA neuron
  • 200-2003 – Stem cell in brain implantation in WashDC
  • 2011 – Behavioral assays that are restored in mice
  • Optogenetics: manipulating – Light on the brain – control animal’s neurons
  • MOA of Graft function
  • Dopamine neurons – Stratium area of the human brain
  • From bench to bedside – WNT boost enhances EN1 expression
  • Neuron melanin induction
  • Manufacturing and QA testing: GMP – Off the shelf Allogenic Product
  • 1,000 human dose equivalents
  • cryopreserve
  • MSK-DA01 is highly enriched for mDA neuron precursors without detectable hESC Contaminants
  • FDA feedback and final steps to IND – PRE-IND MEETING: 2014, 2016
  • GLP STUDIES:
  • TUMORIGENICITY, BIODISTRIBUTION AND TOXISITY
  • HISTOLOGY OF FINAL PRODUCT
  • CLINICAL TRIAL DESIGN – STEM-PD – MSK and Weill Cornell Medicine
  • HLA expression is absent in edited iPSC with expression of HLA-E to block NK clearance
  • FUTURE: CRISPR
  • ATLaS-PD – assessing the longitudinal Symptoms/signs to moderate of severe stage
  • Development of a new PD therapy from Pluripotent Stem Cells
  • BlueRock Therapeutics – MSK-PD – Start up – $240Million funding
  • Stem cell based dopamine therapy for PD
  • Immunosuppression for 12 months
  • defined levodopa response > 45% improvement
  • Conclusions
  • Cell banks for clinical trials
  • NY state Stem cell science consortia

http://www.brandeis.edu/rosenstiel/images/pdfs/gabbay21program.pdf

Read Full Post »


New CRISPR Approach Transforms Skin Cells into Pluripotent Stem Cells

Reporter: Irina Robu, PhD

Dr. Timo Otonkoski, University of Helsinki and Dr.Juha Kere, King’s College London succeeded on reprograming skin cells into pluripotent stem cells by activating cell’s own genes using gene editing technology, CRISPR-Cas9-based gene activation (CRISPRa) that can be used to activate genes. The method uses a blunt version of Cas9 ‘gene scissors’ that does not cut DNA and can consequently be used to activate gene expression without mutating the genome. Previously, reprogramming was only possible by artificially introducing the critical transformation genes known as Yamanaka Factors into skin cells where they are normally inactive.

According to a study that is published in Nature Communication, called Human Pluripotent Reprogramming with CRISPR activators which show that CRISPRa is an attractive tool for cellular reprogramming applications due to its high multiplex capacity and direct alignment of endogenous loci. In the article, it is presented that reprogramming of primary human dermal fibroblasts to induced pluripotent stem cells with CRISPRa, the aimed at endogenous cells. The data shows that human body cells can only be reprogrammed into iPS cells with CRISPRa, and the findings reveal the involvement of EEA motif-associated mechanisms in cellular reprogramming.

The discovery also advocates that it might be likely to improve many other reprogramming tasks by addressing genetic elements that are typical of the intended target cell type. According to Jere Weltner, PhD student working on the project “the technology can find practical application in biobanking and many other applications of tissue technology.

SOURCE

https://www.sciencedaily.com/releases/2018/07/180706091723.htm

 

Read Full Post »


Reporter and Curator: Dr. Sudipta Saha, Ph.D.

 

A heart-healthy diet has been the basis of atherosclerotic cardiovascular disease (ASCVD) prevention and treatment for decades. The potential cardiovascular (CV) benefits of specific individual components of the “food-ome” (defined as the vast array of foods and their constituents) are still incompletely understood, and nutritional science continues to evolve.

 

The scientific evidence base in nutrition is still to be established properly. It is because of the complex interplay between nutrients and other healthy lifestyle behaviours associated with changes in dietary habits. However, several controversial dietary patterns, foods, and nutrients have received significant media exposure and are stuck by hype.

 

Decades of research have significantly advanced our understanding of the role of diet in the prevention and treatment of ASCVD. The totality of evidence includes randomized controlled trials (RCTs), cohort studies, case-control studies, and case series / reports as well as systematic reviews and meta-analyses. Although a robust body of evidence from RCTs testing nutritional hypotheses is available, it is not feasible to obtain meaningful RCT data for all diet and health relationships.

 

Studying preventive diet effects on ASCVD outcomes requires many years because atherosclerosis develops over decades and may be cost-prohibitive for RCTs. Most RCTs are of relatively short duration and have limited sample sizes. Dietary RCTs are also limited by frequent lack of blinding to the intervention and confounding resulting from imperfect diet control (replacing 1 nutrient or food with another affects other aspects of the diet).

 

In addition, some diet and health relationships cannot be ethically evaluated. For example, it would be unethical to study the effects of certain nutrients (e.g., sodium, trans fat) on cardiovascular disease (CVD) morbidity and mortality because they increase major risk factors for CVD. Epidemiological studies have suggested associations among diet, ASCVD risk factors, and ASCVD events. Prospective cohort studies yield the strongest observational evidence because the measurement of dietary exposure precedes the development of the disease.

 

However, limitations of prospective observational studies include: imprecise exposure quantification; co-linearity among dietary exposures (e.g., dietary fiber tracks with magnesium and B vitamins); consumer bias, whereby consumption of a food or food category may be associated with non-dietary practices that are difficult to control (e.g., stress, sleep quality); residual confounding (some non-dietary risk factors are not measured); and effect modification (the dietary exposure varies according to individual/genetic characteristics).

 

It is important to highlight that many healthy nutrition behaviours occur with other healthy lifestyle behaviours (regular physical activity, adequate sleep, no smoking, among others), which may further confound results. Case-control studies are inexpensive, relatively easy to do, and can provide important insight about an association between an exposure and an outcome. However, the major limitation is how the study population is selected or how retrospective data are collected.

 

In nutrition studies that involve keeping a food diary or collecting food frequency information (i.e., recall or record), accurate memory and recording of food and nutrient intake over prolonged periods can be problematic and subject to error, especially before the diagnosis of disease.

 

The advent of mobile technology and food diaries may provide opportunities to improve accuracy of recording dietary intake and may lead to more robust evidence. Finally, nutrition science has been further complicated by the influences of funding from the private sector, which may have an influence on nutrition policies and practices.

 

So, the future health of the global population largely depends on a shift to healthier dietary patterns. Green leafy vegetables and antioxidant suppliments have significant cardio-protective properties when consumed daily. Plant-based proteins are significantly more heart-healthy compared to animal proteins.

 

However, in the search for the perfect dietary pattern and foods that provide miraculous benefits, consumers are vulnerable to unsubstantiated health benefit claims. As clinicians, it is important to stay abreast of the current scientific evidence to provide meaningful and effective nutrition guidance to patients for ASCVD risk reduction.

 

Available evidence supports CV benefits of nuts, olive oil and other liquid vegetable oils, plant-based diets and plant-based proteins, green leafy vegetables, and antioxidant-rich foods. Although juicing may be of benefit for individuals who would otherwise not consume adequate amounts of fresh fruits and vegetables, caution must be exercised to avoid excessive calorie intake. Juicing of fruits / vegetables with pulp removal increases calorie intake. Portion control is necessary to avoid weight gain and thus cardiovascular health.

 

There is currently no evidence to supplement regular intake of antioxidant dietary supplements. Gluten is an issue for those with gluten-related disorders, and it is important to be mindful of this in routine clinical practice; however, there is no evidence for CV or weight loss benefits, apart from the potential caloric restriction associated with a gluten free diet.

 

References:

 

https://www.ncbi.nlm.nih.gov/pubmed/28254181

 

https://www.sciencedirect.com/science/article/pii/S0735109713060294?via%3Dihub

 

http://circ.ahajournals.org/content/119/8/1161

 

http://refhub.elsevier.com/S0735-1097(17)30036-0/sref6

 

https://www.scopus.com/record/display.uri?eid=2-s2.0-0031709841&origin=inward&txGid=af40773f7926694c7f319d91efdcd40c

 

https://www.magonlinelibrary.com/doi/10.12968/hosp.2000.61.4.1875

 

https://jamanetwork.com/journals/jamainternalmedicine/article-abstract/2548255

 

https://pharmaceuticalintelligence.com/2018/05/31/supplements-offer-little-cv-benefit-and-some-are-linked-to-harm-in-j-am-coll-cardiol/

Read Full Post »


Lesson 9 Cell Signaling:  Curations and Articles of reference as supplemental information for lecture section on WNTs: #TUBiol3373

Stephen J. Wiilliams, Ph.D: Curator

UPDATED 4/23/2019

This has an updated lesson on WNT signaling.  Please click on the following and look at the slides labeled under lesson 10

cell motility 9b lesson_2018_sjw

Remember our lessons on the importance of signal termination.  The CANONICAL WNT signaling (that is the β-catenin dependent signaling)

is terminated by the APC-driven degradation complex.  This leads to the signal messenger  β-catenin being degraded by the proteosome.  Other examples of growth factor signaling that is terminated by a proteosome-directed include the Hedgehog signaling system, which is involved in growth and differentiation as well as WNTs and is implicated in various cancers.

A good article on the Hedgehog signaling pathway is found here:

The Voice of a Pathologist, Cancer Expert: Scientific Interpretation of Images: Cancer Signaling Pathways and Tumor Progression

All images in use for this article are under copyrights with Shutterstock.com

Cancer is expressed through a series of transformations equally involving metabolic enzymes and glucose, fat, and protein metabolism, and gene transcription, as a result of altered gene regulatory and transcription pathways, and also as a result of changes in cell-cell interactions.  These are embodied in the following series of graphics.

Figure 1: Sonic_hedgehog_pathwaySonic_hedgehog_pathway

The Voice of Dr. Larry

The figure shows a modification of nuclear translocation by Sonic hedgehog pathway. The hedgehog proteins have since been implicated in the development of internal organs, midline neurological structures, and the hematopoietic system in humans. The Hh signaling pathway consists of three main components: the receptor patched 1 (PTCH1), the seven transmembrane G-protein coupled receptor smoothened (SMO), and the intracellular glioma-associated oncogene homolog (GLI) family of transcription factors.5The GLI family is composed of three members, including GLI1 (gene activating), GLI2 (gene activating and repressive), and GLI3 (gene repressive).6 In the absence of an activating signal from either Shh, Ihh or Dhh, PTCH1 exerts an inhibitory effect on the signal transducer SMO, preventing any downstream signaling from occurring.7 When Hh ligands bind and activate PTCH1, the inhibition on SMO is released, allowing the translocation of SMO into the cytoplasm and its subsequent activation of the GLI family of transcription factors.

 

And from the review of  Elaine Y. C. HsiaYirui Gui, and Xiaoyan Zheng   Regulation of Hedgehog Signaling by Ubiquitination  Front Biol (Beijing). 2015 Jun; 10(3): 203–220.

the authors state:

Finally, termination of Hh signaling is also important for controlling the duration of pathway activity. Hh induced ubiquitination and degradation of Ci/Gli is the most well-established mechanism for limiting signal duration, and inhibiting this process can lead to cell patterning disruption and excessive cell proliferation (). In addition to Ci/Gli, a growing body of evidence suggests that ubiquitination also plays critical roles in regulating other Hh signaling components including Ptc, Smo, and Sufu. Thus, ubiquitination serves as a general mechanism in the dynamic regulation of the Hh pathway.

Overview of Hedgehog signaling showing the signal termination by ubiquitnation and subsequent degradation of the Gli transcriptional factors. obtained from Oncotarget 5(10):2881-911 · May 2014. GSK-3B as a Therapeutic Intervention in Cancer

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Note that in absence of Hedgehog ligands Ptch inhibits Smo accumulation and activation but upon binding of Hedgehog ligands (by an autocrine or paracrine fashion) Ptch is now unable to inhibit Smo (evidence exists that Ptch is now targeted for degradation) and Smo can now inhibit Sufu-dependent and GSK-3B dependent induced degradation of Gli factors Gli1 and Gli2.  Also note the Gli1 and Gli2 are transcriptional activators while Gli3 is a transcriptional repressor.

UPDATED 4/16/2019

Please click on the following links for the Powerpoint presentation for lesson 9.  In addition click on the mp4 links to download the movies so you can view them in Powerpoint slide 22:

cell motility 9 lesson_SJW 2019

movie file 1:

Tumorigenic but noninvasive MCF-7 cells motility on an extracellular matrix derived from normal (3DCntrol) or tumor associated (TA) fibroblasts.  Note that TA ECM is “soft” and not organized and tumor cells appear to move randomly if  much at all.

Movie 2:

 

Note that these tumorigenic and invasive MDA-MB-231 breast cancer cells move in organized patterns on organized ECM derived from Tumor Associated (TA) fibroblasts than from the ‘soft’ or unorganized ECM derived from normal  (3DCntrl) fibroblasts

 

The following contain curations of scientific articles from the site https://pharmaceuticalintelligence.com  intended as additional reference material  to supplement material presented in the lecture.

Wnts are a family of lipid-modified secreted glycoproteins which are involved in:

Normal physiological processes including

A. Development:

– Osteogenesis and adipogenesis (Loss of wnt/β‐catenin signaling causes cell fate shift of preosteoblasts from osteoblasts to adipocytes)

  – embryogenesis including body axis patterning, cell fate specification, cell proliferation and cell migration

B. tissue regeneration in adult tissue

read: Wnt signaling in the intestinal epithelium: from endoderm to cancer

And in pathologic processes such as oncogenesis (refer to Wnt/β-catenin Signaling [7.10]) and to your Powerpoint presentation

 

The curation Wnt/β-catenin Signaling is a comprehensive review of canonical and noncanonical Wnt signaling pathways

 

To review:

 

 

 

 

 

 

 

 

 

 

 

Activating the canonical Wnt pathway frees B-catenin from the degradation complex, resulting in B-catenin translocating to the nucleus and resultant transcription of B-catenin/TCF/LEF target genes.

Fig. 1 Canonical Wnt/FZD signaling pathway. (A) In the absence of Wnt signaling, soluble β-catenin is phosphorylated by a degradation complex consisting of the kinases GSK3β and CK1α and the scaffolding proteins APC and Axin1. Phosphorylated β-catenin is targeted for proteasomal degradation after ubiquitination by the SCF protein complex. In the nucleus and in the absence of β-catenin, TCF/LEF transcription factor activity is repressed by TLE-1; (B) activation of the canonical Wnt/FZD signaling leads to phosphorylation of Dvl/Dsh, which in turn recruits Axin1 and GSK3β adjacent to the plasma membrane, thus preventing the formation of the degradation complex. As a result, β-catenin accumulates in the cytoplasm and translocates into the nucleus, where it promotes the expression of target genes via interaction with TCF/LEF transcription factors and other proteins such as CBP, Bcl9, and Pygo.

NOTE: In the canonical signaling, the Wnt signal is transmitted via the Frizzled/LRP5/6 activated receptor to INACTIVATE the degradation complex thus allowing free B-catenin to act as the ultimate transducer of the signal.

Remember, as we discussed, the most frequent cancer-related mutations of WNT pathway constituents is in APC.

This shows how important the degradation complex is in controlling canonical WNT signaling.

Other cell signaling systems are controlled by protein degradation:

A.  The Forkhead family of transcription factors

Read: Regulation of FoxO protein stability via ubiquitination and proteasome degradation

B. Tumor necrosis factor α/NF κB signaling

Read: NF-κB, the first quarter-century: remarkable progress and outstanding questions

1.            Question: In cell involving G-proteins, the signal can be terminated by desensitization mechanisms.  How is both the canonical and noncanonical Wnt signal eventually terminated/desensitized?

We also discussed the noncanonical Wnt signaling pathway (independent of B-catenin induced transcriptional activity).  Note that the canonical and noncanonical involve different transducers of the signal.

Noncanonical WNT Signaling

Note: In noncanonical signaling the transducer is a G-protein and second messenger system is IP3/DAG/Ca++ and/or kinases such as MAPK, JNK.

Depending on the different combinations of WNT ligands and the receptors, WNT signaling activates several different intracellular pathways  (i.e. canonical versus noncanonical)

 

In addition different Wnt ligands are expressed at different times (temporally) and different cell types in development and in the process of oncogenesis. 

The following paper on Wnt signaling in ovarian oncogenesis shows how certain Wnt ligands are expressed in normal epithelial cells but the Wnt expression pattern changes upon transformation and ovarian oncogenesis. In addition, differential expression of canonical versus noncanonical WNT ligands occur during the process of oncogenesis (for example below the authors describe the noncanonical WNT5a is expressed in normal ovarian  epithelia yet WNT5a expression in ovarian cancer is lower than the underlying normal epithelium. However the canonical WNT10a, overexpressed in ovarian cancer cells, serves as an oncogene, promoting oncogenesis and tumor growth.

Wnt5a Suppresses Epithelial Ovarian Cancer by Promoting Cellular Senescence

Benjamin G. Bitler,1 Jasmine P. Nicodemus,1 Hua Li,1 Qi Cai,2 Hong Wu,3 Xiang Hua,4 Tianyu Li,5 Michael J. Birrer,6Andrew K. Godwin,7 Paul Cairns,8 and Rugang Zhang1,*

A.           Abstract

Epithelial ovarian cancer (EOC) remains the most lethal gynecological malignancy in the US. Thus, there is an urgent need to develop novel therapeutics for this disease. Cellular senescence is an important tumor suppression mechanism that has recently been suggested as a novel mechanism to target for developing cancer therapeutics. Wnt5a is a non-canonical Wnt ligand that plays a context-dependent role in human cancers. Here, we investigate the role of Wnt5a in regulating senescence of EOC cells. We demonstrate that Wnt5a is expressed at significantly lower levels in human EOC cell lines and in primary human EOCs (n = 130) compared with either normal ovarian surface epithelium (n = 31; p = 0.039) or fallopian tube epithelium (n = 28; p < 0.001). Notably, a lower level of Wnt5a expression correlates with tumor stage (p = 0.003) and predicts shorter overall survival in EOC patients (p = 0.003). Significantly, restoration of Wnt5a expression inhibits the proliferation of human EOC cells both in vitro and in vivo in an orthotopic EOC mouse model. Mechanistically, Wnt5a antagonizes canonical Wnt/β-catenin signaling and induces cellular senescence by activating the histone repressor A (HIRA)/promyelocytic leukemia (PML) senescence pathway. In summary, we show that loss of Wnt5a predicts poor outcome in EOC patients and Wnt5a suppresses the growth of EOC cells by triggering cellular senescence. We suggest that strategies to drive senescence in EOC cells by reconstituting Wnt5a signaling may offer an effective new strategy for EOC therapy.

Oncol Lett. 2017 Dec;14(6):6611-6617. doi: 10.3892/ol.2017.7062. Epub 2017 Sep 26.

Clinical significance and biological role of Wnt10a in ovarian cancer. 

Li P1Liu W1Xu Q1Wang C1.

Ovarian cancer is one of the five most malignant types of cancer in females, and the only currently effective therapy is surgical resection combined with chemotherapy. Wnt family member 10A (Wnt10a) has previously been identified to serve an oncogenic function in several tumor types, and was revealed to have clinical significance in renal cell carcinoma; however, there is still only limited information regarding the function of Wnt10a in the carcinogenesis of ovarian cancer. The present study identified increased expression levels of Wnt10a in two cell lines, SKOV3 and A2780, using reverse transcription-polymerase chain reaction. Functional analysis indicated that the viability rate and migratory ability of SKOV3 cells was significantly inhibited following Wnt10a knockdown using short interfering RNA (siRNA) technology. The viability rate of SKOV3 cells decreased by ~60% compared with the control and the migratory ability was only ~30% of that in the control. Furthermore, the expression levels of β-catenin, transcription factor 4, lymphoid enhancer binding factor 1 and cyclin D1 were significantly downregulated in SKOV3 cells treated with Wnt10a-siRNA3 or LGK-974, a specific inhibitor of the canonical Wnt signaling pathway. However, there were no synergistic effects observed between Wnt10a siRNA3 and LGK-974, which indicated that Wnt10a activated the Wnt/β-catenin signaling pathway in SKOV3 cells. In addition, using quantitative PCR, Wnt10a was overexpressed in the tumor tissue samples obtained from 86 patients with ovarian cancer when compared with matching paratumoral tissues. Clinicopathological association analysis revealed that Wnt10a was significantly associated with high-grade (grade III, P=0.031) and late-stage (T4, P=0.008) ovarian cancer. Furthermore, the estimated 5-year survival rate was 18.4% for patients with low Wnt10a expression levels (n=38), whereas for patients with high Wnt10a expression (n=48) the rate was 6.3%. The results of the present study suggested that Wnt10a serves an oncogenic role during the carcinogenesis and progression of ovarian cancer via the Wnt/β-catenin signaling pathway.

Targeting the Wnt Pathway includes curations of articles related to the clinical development of Wnt signaling inhibitors as a therapeutic target in various cancers including hepatocellular carcinoma, colon, breast and potentially ovarian cancer.

 

2.         Question: Given that different Wnt ligands and receptors activate different signaling pathways, AND  WNT ligands  can be deferentially and temporally expressed  in various tumor types and the process of oncogenesis, how would you approach a personalized therapy targeting the WNT signaling pathway?

3.         Question: What are the potential mechanisms of either intrinsic or acquired resistance to Wnt ligand antagonists being developed?

 

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

Targeting the Wnt Pathway [7.11]

Wnt/β-catenin Signaling [7.10]

Cancer Signaling Pathways and Tumor Progression: Images of Biological Processes in the Voice of a Pathologist Cancer Expert

e-Scientific Publishing: The Competitive Advantage of a Powerhouse for Curation of Scientific Findings and Methodology Development for e-Scientific Publishing – LPBI Group, A Case in Point 

Electronic Scientific AGORA: Comment Exchanges by Global Scientists on Articles published in the Open Access Journal @pharmaceuticalintelligence.com – Four Case Studies

 

Read Full Post »

Older Posts »