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Larry H Bernstein, MD, FCAP, Contributor

https://pharmaceuticalintelligence.com/5-6-2014/larryhbern/ The Discovery_and_Properties_of_Avemar – Fermented_ Wheat_Germ_Extract:_Carcinogenesis_Suppressor

The following discussion will be a review of the current interest in Avemar, a nontoxic, fermentation product of wheat germ extract, garnering interest with respect to alternative and complementary medicinal use.

Extracts from an interview by Sandra Cascio with Mate Hidvegi

Mate’s Transylvania Professor Lajos David was the organizer of the Department of Pharmacy of the University of Szeged in the 1920’s. He was elected as the Dean of the Faculty of Medicine, the first and only pharmacist who reached this high position at the University since. Dr. Hidvegy’s grandfather was a devout Roman catholic, who publicly opposed Nazi persecution of Jews during the Holocaust. One of his colleagues and, perhaps his best friend, was Albert Szent­Gyorgyi, the Nobel laureate who discovered vitaminC. Szent­Gyorgyi moved to the United States after World War II, where he turned to studies of muscle biochemistry. In his later years he turned to cancer research. He  theorized that a revolutionary anticancer drug could be based upon vitamin C combined with methoxy­substituted benzoquinones, the precursors of which can be found in wheat germ. After completion of the PhD, Dr. Hidvegi spent two years with the Wheat Grain Trust in Winnipeg, Canada, before returning to Hungary in 1990.  He decided to followthepathwaythat Szent­Gyorgyi was now engaged intocompletehisgoals.He contacted anoldfriend,GaborFodor, a brilliantchemist, also a collaborator withSzent­Gyorgyiincancerresearch.

He wasinvited by Hermann Esterbauer, the head of the Institute of Biochemistry at the University of Graz, to work in his laboratory. Thanks to the generosity of Professor Esterbauer,  he accomplished much at Graz  together with his student, Dr. Rita Farkas.  It was soon after Szent­-Gyorgyi’s death when, with the help of Dr. Fodor, they prepared the chemicals to make the drug Szent­-Gyorgyi had intended to make, with encouragement from the great quantum­ biochemist, Janos Ladik.  They made wheat germ extracts with the highest free benzoquinone content.This required a  fermentation process to liberate the benzoquinone moieties from the chemical bonds which keep them in natural forms: in glycosides. He recalls the purple colored active molecules in the fermentation liquid. Living cells with their exo­ and endo­enzymes are used to split bonds and make new molecules. This is also true for the manufacturing process of Avemar. This extract contains new molecules which cannot be found elsewhere.

“WhenAvemar was voted by the majority of the more than 50,000 professionals for NutrAward, it became obvious that this product is of biological efficacy  plus safety, and it is based on good science.” It received the financial support needed. From this, he was able to complete the experiments and get the approval for the registration. The time arrived when he really had to give a name to the product which had only had a code name. One late night it just came: Avemar, from the Latin prayer: Ave Maria.

Avemar with widely used chemotherapeutic drugs completely inhibited the development of metastases. Exploring its whole activity profile might even take a lifetime of research. So far he has supervised Avemar research done in Hungary, Israel, the United States, Austria, Italy, Spain, Slovakia, the Czech Republic, Germany,the United Kingdom, Russia, Australia, Korea, Vietnam. It has been a good experience to see the scientific interest it has generated worldwide. In 2009, Dr. Hidvegy received an invitation from the Nobel laureate, James Watson, co­discoverer of DNA’s double helix. It was a great honor. Avemar, he hopes,will be a significant cancer drug.

Mate Hidvegi was born in Budapest, Hungary, in 1955. He studied, then  taughat what is now Budapest University of Technology  and Economics.  After finishing university, he worked in the cereal industry and was co­developer of patented feed advisory system based on near infrared ingredient      data. In Hungary, Hidvegi was one of the pioneers in the development of           technologies for large ­scale production of instantized extracts for  therapeutic use.

 

Carcinogenesis vol.22 no.10 pp.1649–1652, 2001

Wheat germ extract inhibits experimental colon carcino-genesis in F-344 rats

Attila Zalatnai, Karoly Lapis, Bela Szende, Erzsebet Raso, Andros Telekes, Akos Resetar, and Mate Hidvegi

 

It has been demonstrated for the first time that a wheat germ extract prevents colonic cancer in laboratory animals. Four-week-old inbred male F-344 rats were used in the study. Colon carcinogenesis was induced by azoxy-methane (AOM). Ten rats served as untreated controls (group 1). For the treatment of the animals in group 2, AOM was dissolved in physiologic saline and the animals were given three weekly subcutaneous injections at 15 mg/kg body weight (b/w). In two additional groups Avemar (MSC), a fermented wheat germ extract standardized to 2,6-dimethoxy-p-benzoquinone was administered as a tentative chemo-preventive agent. MSC was dissolved in water and was given by gavage at a dose of 3 g/kg b/w once a day. In group 3, animals started to receive MSC 2 weeks prior to the first injection of AOM daily and continuously thereafter until they were killed 32 weeks later. In group 4 only the basal diet and MSC were administered. At the end of the experiment all the rats were exsanguinated under a light ether anesthesia and necropsied. Percentage of animals developing colon tumors and number of tumors per animals: group 1 – 0 and 0; group 2– 83.0 and 2.3; group 3 – 44.8 (P ≤ 0.001) and 1.3 (P ≤ 0.004); group 4 – 0 and 0. All the tumors were histologically neoplastic. The numbers of the aberrant crypt foci (ACF) per area (cm2) in group 2 were 4.85 while in group 3 the ACF numbers were 2.03 only (P ≤ 0.0001).
Table I. Macroscopic findings in the large intestines of F-344 rats treated with MSC or MSC +  AOM
No. of animals     w/tumorw   Average
# tumors
Average
diameter

N

1 Untreated
controls (10)
0/10 0/10
2.  AOM (47) 39/47
(83.0%)
2.3 ­+ 0.21
(range 1–8)
2.35 +
0.25
3.   MSC +
AOM (29)
13/29
(44.8%)
1.3 + 0.17
(range 1–3)
2.21 +
0.12
4.  MSC (9) 0/9 0/9
Fig. 1. Experimental schedule. Colon carcinogenesis was induced by three consecutive s.c. doses of AOM 1 week apart in F-344 rats. Oral administration of MSC was started 2 weeks before the carcinogen treatments. All the animals were killed at the end of the experiment, e.g. on the 32nd week.  (not shown)

 

Summing up, although the chemoprevention of colon cancers (and their pre-neoplastic lesions) has well and long been established and could be achieved by totally different compounds, the mechanisms have still remained to be clarified. This is also true for MSC.

The exact mechanism by which the fermented wheat germ concentration can prevent colon cancer is still partly unknown. MSC did inhibit the AOM-induced ACF and colon neoplasm formation, the multiplicity of the tumors, apparently acting in the initiation phase. Regarding this, we can hypothesize that MSC acts as an immunomodulator.

 

Wheat Germ Extract Decreases Glucose Uptake and RNARibose Formation but Increases Fatty Acid Synthesis in MIAPancreatic Adenocarcinoma Cell

LG Boros, K Lapis, B Szende, R Tömösközi-Farkas, Ádám Balogh, …., and M Hidvégi

UCLA School of Medicine, Harbor-UCLA Research and Education Institute, Torrance, Ca.; First Institute of Pathology and Experimental Cancer Research, Semmelweis  Medical University, Budapest, Hungary; Central Food Research Institute, Budapest, Hungary; Department of Surgery, Albert Szent-Gyorgyi Medical and Pharmaceutical Center, School of General Medicine, University of Szeged, Szeged, Hungary; Department of Biochemistry and Molecular Biology, Institut d’Investigacions Biomediques August Pi i Sunyer, University of Barcelona, Barcelona, Spain; andDepartment of Biochemistryand Food Technology, Technical University of Budapest and Biromedicina Company, Budapest, Hungary

Pancreas 2001; 23 (2), pp. 141–147

Summary: The fermented wheat germ extract with standardized composition has potent tumor inhibitory properties. The fermented wheat germ extract controls tumor propagation. The authors show that this extract induces profound metabolic changes in cultured MIA pancreatic adenocarcinoma cells when the [1,2- 13C2] glucose isotope is used as the single tracer with biologic gas chromatography–mass spectrometry.

MIA cells treated with 0.1, 1, and 10 mg/mL wheat  germ extract showed a dose-dependent decrease in cell glucose consumption, consumption, uptake of isotope into ribosomal RNA (2.4%, 9.4%, and 8.0%), and release of 13CO2 . Conversely, direct glucose oxidation and ribose recycling in the pentose cycle showed a dose-dependent increase of 1.2%, 20.7%, and 93.4%. The newly synthesized fraction of cell palmitate and the 13C enrichment of acetyl units were also increased with all doses of wheat germ extract.

The fermented wheat germ extract controls tumor propagation primarily by regulating glucose carbon redistribution between cell proliferation–related and cell differentiation–related macromolecules. Wheat germ extract treatment is likely associated with the phosphor-ylation and transcriptional regulation of metabolic enzymes that are involved in glucose carbon redistribution between cell the direct oxidative degradation of glucose,proliferation–related structural and functional macromolecules(RNA, DNA) and the direct oxidative degradation and survival of pancreatic adenocarcinoma cells in culture.

Key Words: Pentose cycle—Ribose synthesis—Fermented wheat germ extract—Nonoxidative glucose metabolism—Cell proliferation—Avemar.

 

Fig 1 glu consumption of MIA pancreatic carcinoma cells in response to WGE

Fig 1 glu consumption of MIA pancreatic carcinoma cells in response to WGE

 

 

 

 

 

 

 

 

 

 

 

Figure 1. Glucose consumption of MIA pancreatic adenocarcinoma cells in response to increasing doses of fermented wheat germ extract (Avemar) treatment after 72 hours of culture. Glucose consumption (measured in milligrams) was estimated by the difference in media glucose content between Avemar-treated and control cultures. MIA cell glucose consumption was significantly inhibited in the presence of either 1 mg/mL (*p < 0.05) or 10 mg/mL (**p < 0.01) Avemar (x + SD;  n = 6).

 

fig-3-rna-syn-of-mia-pancreatic-carcinoma-cells-in-response-to-wge.jpg

fig-3-rna-syn-of-mia-pancreatic-carcinoma-cells-in-response-to-wge.jpg

 

 

 

 

 

 

 

 

 

 

 

Figure 3. Ribosomal RNA synthesis of MIA pancreatic adenocarcinoma cells in response to increasing doses of fermented wheat germ extract (Avemar) treatment after 72 hours of culture. Glucose carbon incorporation into ribose isolated from ribosomal RNA is expressed as molar enrichment. The dose-dependent decrease in of rRNA after Avemar treatment indicates that ribosomal RNA synthesis is the primary site significantly affected by all doses of Avemar treatment with a maximum decrease of 29% after 10 mg/mL treatment (x + SD; n = 9; *p < 0.05, **p < 0.01).

changes in metabolic activity indicate that Avemar treatment affects cell metabolism primarily by decreasing glucose uptake and nucleic acid ribose synthesis while increasing glucose oxidation through the oxidative reactions of the pentose cycle and fatty acid  synthesis from glucose carbon. The effect of Avemar treatment on lactate production and TCA cycle anapleurotic flux compared with glucose oxidation is less prominent

 

Fermented wheat germ extract induces apoptosis and downregulation of major histocompatibility complex class I proteins in tumor T and B cell lines

R FAJKA-BOJA, M HIDVÉGI, Y SHOENFELD, G  ION, D DEMYDENKO, R TÖMÖSKÖZI-FARKAS, et al.

INTL J ONCOLOGY 2002; 20: 563-570.

Lymphocyte Signal Transduction Laboratory, Institute of Genetics, and Cytokine Group, Institute of Biochemistry, Biological Research Center of the Hungarian Academy of Sciences, Szeged; Department of Biochemistry and Food Technology, Budapest University of Technology and Economics, Budapest, Hungary; Department of Medicine ‘B’, Center for Autoimmune Diseases, Sheba Medical Center, Tel-Hashomer, Israel; Central Food Research Institute; National Institute of Oncology; Biromedicina Co., Budapest, Hungary
Abstract. The fermented wheat germ extract (code name:  on cyto-fluorimeter using a monoclonal antibody to the  MSC, trade name: Avemar), with standardized benzoquinone non-polymorphic region of the human MHC class I. MSC  content has been shown to inhibit tumor propagation and stimulated tyrosine phosphorylation of intracellular proteins metastases formation in vivo. The aim of this study was to  understand the molecular and cellular mechanisms of the anti-tumor effect of MSC. Therefore, we have designed in vitro model experiments using T and B tumor lymphocytic cell lines. As a result of the MSC treatment, cell surface MHC class I proteins was downregulated by 70-85% compared to the non-stimulated control.

Prominent apoptosis of and the influx of extracellular Ca2+ resulted in elevation of the amount of the intracellular Ca2+ concentration. 20-40% was detected upon 24 h of MSC treatment of the cell lines. Apoptosis was measured with cytofluorimetry by staining the DNA with propidium iodide and detecting the ‘sub-G ’ cell population.

Tyrosine phosphorylation of intra-cellular proteins and elevation of the intracellular Ca2+ concentration were examined using immunoblotting with anti-phosphotyrosine antibody and cytofluorimetry by means of Ca2+ sensitive fluorescence dyes, Fluo-3AM and FuraRed-AM, respectively. MSC did not induce a similar degree of apoptosis in healthy peripheral blood mononuclear cells.

Inhibition of the cellular tyrosine phosphatase activity or Ca2+ influx resulted in the opposite effect – increasing or diminishing the Avemar induced apoptosis as well as the MHC class I downregulation. The level of the cell surface MHC class I molecules was analysed with indirect immunofluorescence. The benzoquinone component (2,6-dimethoxi-p-benzoquinone) in MSC induced similar apoptosis and downregulation of the MHC class I molecules in the tumor T and B cell lines to that of MSC. These results suggest that MSC acts on lymphoid tumor cells by reducing MHC class I expression and selectively promoting apoptosis of tumor cells on a tyrosine phosphorylation and Ca2+ influx dependent way.  One of the components in MSC, 2,6-dimethoxi-p-benzoquinone was shown to be an important factor in MSC mediated cell response.

 

Abbreviations:MHC, major histocompatibility complex;NK, natural killer;DMBQ, 2,6-dimethoxi-p-benzoquinone; FCS, fetal calf serum;PBMC, peripheral bloodmononuclear cells; TCR, T cell receptor;BCR, B cell receptor; mAb, monoclonal antibody;PMSF,phenylmethyl-sulfonylfluoride;pNPP, para-nitrophenyl-phosphate; PHA,phytohemagglutinineKey words: fermented wheat germ extract, Avemar, MSC, 2+ benzoquinone, tyrosine phosphorylation, intracellular Ca , CD45, tyrosine phosphatase, MHC class I downregulation, apoptosis

 

fig-4-apoptosis-of-t-cell-lines-induced-by-avamer.jpg

fig-4-apoptosis-of-t-cell-lines-induced-by-avamer.jpg

 

 

 

 

 

Figure 4. Apoptosis of tumor T cell lines and healthy lymphocytes upon MSC treatment. Jurkat cells were treated with 1 mg/ml MSC or .3 µg/ml DMBQ and PBMC were treated with 1 mg/ml
MSC for 24 h (A) or Jurkat cells were treated for 12 h (thick line in panel B). Control cells were left unstimulated (black bars in panel A or thin line on panel B). Apoptotic cells were enumerated
with the DNA analysis of the ‘sub-G ’ population (A) or with staining the cells with FITC1 labeled Annexin V
(B). Representative experiments are shown. The difference between the % of apoptosis in the case of treated and non-treated Jurkat cells was significant (MSC, p<0.001, n=14; DMBQ, p<0.05, n=3,
using  paired, two-tailed t-test). No difference was found for PBMC (n=2).

MSC treatment causes prominent apoptosis in lymphoid tumor cells but it does not induce apoptosis of healthy resting mononuclear cells. Moreover, although MSC blocks the proliferation of PBM cells stimulated with PHA, it does not induce apoptosis in PHA stimulated cells (data not shown).

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Multivitamins – Don’t help Extend Life or ward off Heart Disease and Improve state of Memory Loss

Reporter: Aviva Lev-Ari, PhD, RN

 

Experts: Don’t Waste Your Money on Multivitamins – Three studies find the supplements don’t help extend life or ward off heart disease and memory loss

http://www.nlm.nih.gov/medlineplus/news/fullstory_143473.html

Monday, December 16, 2013

HealthDay news image 

MONDAY, Dec. 16, 2013 (HealthDay News) — With three new studies finding that a daily multivitamin won’t help boost the average American’s health, the experts behind the research are urging people to abandon use of the supplements.

The studies found that popping a daily multivitamin didn’t ward off heart problems or memory loss, and wasn’t tied to a longer life span.

The studies, published in the Dec. 17 issue of the journal Annals of Internal Medicine, found that multivitamin and mineral supplements did not work any better than placebo pills.

Dietary supplements are a multibillion-dollar industry in the United States, and multivitamins account for nearly half of all vitamin sales, according to the U.S. Office of Dietary Supplements.

But a growing body of evidence suggests that multivitamins offer little or nothing in the way of health benefits, and some studies suggest that high doses of certain vitamins might cause harm.

As a result, the authors behind the new research said it’s time for most people to stop taking them.

“We believe that it’s clear that vitamins are not working,” said Dr. Eliseo Guallar, a professor of epidemiology at the Johns Hopkins Bloomberg School of Public Health.

In a strongly worded editorial on the three studies, Guallar and his co-authors urged people to stop spending money on multivitamins.

Even a representatives of the vitamin industry asked people to temper their hopes about dietary supplements.

“We all need to manage our expectations about why we’re taking multivitamins,” Duffy MacKay, vice president of scientific and regulatory affairs for the Council for Responsible Nutrition, a trade group that represents supplement manufacturers, said in a prepared statement.

“Research shows that the two main reasons people take multivitamins are for overall health and wellness and to fill in nutrient gaps,” MacKay said. “Science still demonstrates that multivitamins work for those purposes, and that alone provides reason for people to take a multivitamin.”

However, Guallar said, it’s not clear that taking supplements to fill gaps in a less-than-perfect diet really translates into any kind of health boost.

“It would be great if all dietary problems could be solved with a pill,” he said. “Unfortunately, that’s not the case.”

For the first study, researchers randomly assigned almost 6,000 male doctors over the age of 65 to take either a daily Centrum Silver multivitamin or a look-alike placebo pill. Every few years, the researchers gave the men a battery of tests over the telephone to check their memories.

The men in the study were in pretty good health to begin with, and 84 percent said they faithfully took their pills each day.

After 12 years, there was no difference in memory problems between the two groups.

“No matter which way we broke it down, there was a null effect,” said study author Jacqueline O’Brien, a research associate at Brigham and Women’s Hospital in Boston. “Supplements are often marketed to have benefits for brain health and things like that, and this is a pretty clear takeaway message.”

The same study, however, had previously found that multivitamins might modestly reduce the risk of cancer and cataracts. Cancer risk was reduced by 8 percent, while the risk of cataracts dropped by 9 percent, compared to a placebo.

In the second study, researchers randomly assigned 1,700 heart attack survivors enrolled in a trial of therapy known as intravenous chelation to a daily regimen of high doses of vitamins and minerals or placebo pills.

Participants were asked to take six large pills a day, and researchers think many developed pill fatigue. Nearly half the participants in each part of the study stopped taking their medication before the end of the study. The average time people stuck with it was about two and a half years.

After an average of 55 months, there was no significant difference between the two groups in a composite measure that counted the number of deaths, second heart attacks, strokes, episodes of serious chest pain and procedures to open blocked arteries.

The third study, a research review, assessed the evidence from 27 studies on vitamin and mineral supplements that included more than 450,000 people. That study, conducted for the U.S. Preventive Services Task Force, found no evidence that supplements offer a benefit for heart disease or that they delay death from any cause. They found only a minimal benefit for cancer risk.

The results of the studies are so clear and consistent, the editorial writers said, that it’s time to stop wasting research money looking for evidence of a benefit.

“The probability of a meaningful effect is so small that it’s not worth doing study after study and spending research dollars on these questions,” Guallar said.

SOURCES: Eliseo Guallar, M.D., professor of epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore; Jacqueline O’Brien, Sc.D., research associate, Brigham and Women’s Hospital, Boston; Dec. 16, 2013, news release, Council for Responsible Nutrition, Washington, D.C.; Dec. 17, 2013, Annals of Internal Medicine

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SOURCES
http://www.nlm.nih.gov/medlineplus/news/fullstory_143473.html

http://consumer.healthday.com/cognitive-health-information-26/brain-health-news-80/experts-don-t-waste-your-money-on-multivitamins-683104.html

 

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Phosphatidyl-5-Inositol Signaling by Pin1

 

Reporter: Larry H Bernstein, MD, FCAP

 

Regulation of Phosphatidylinositol-5-Phosphate Signaling by Pin1 Determines Sensitivity to Oxidative Stress

Willem-Jan Keune et al.
Increasing the abundance of the phospholipid PtdIns5P protects cells from oxidative stress.
Science Signaling   27 nov 2012; 5:252.
  1. T cell receptor (TCR) and costimulatory molecule mediated signaling
  2. culminate in maximal cytokine mRNA production and stability.
The transcriptional responses to co-stimulatory T cell signaling involve calcineurin and NF-AT, which
    • can be antagonized by interference with the cis-trans peptidyl-prolyl isomerases (PPIase), cyclophilin A and FKBP.
Signaling molecules downstream of CD28
    • which are essential for the stabilization of cytokine mRNAs are largely unknown.

Pin1, a third member of the PPIase family

    • mediates the post-transcriptional regulation of Th1 cytokines by activated T cells.

Blockade of Pin1 by pharmacologic or genetic means

  • greatly attenuated IFN-γ, IL-2 and CXCL-10 mRNA
    • stability,
    • accumulation and
    • protein expression after cell activation.

In vivo, Pin1 blockade prevented

  • both the acute and chronic rejection of MHC mismatched, orthotopic rat lung transplants by
  • reducing the expression of IFN-γ and CXCL-10.

Combined transcriptional and post-transcriptional blockade with

    • cyclosporine A and the Pin1 inhibitor, juglone, was synergistic.

These data suggest Pin1 inhibitors should be explored for use as immunosuppressants and employed with available calcineurin inhibitors to reduce toxicity and enhance effectiveness.
Esnault S, Braun RK, Shen Z-J, Xiang Z, Heninger E, et al. (2007)
Pin1 Modulates the Type 1 Immune Response. PLoS ONE 2(2): e226.  http://dx. doi.org/10.1371/journal.pone.0000226

Mixed-lineage kinase 3 phosphorylates prolyl-isomerase Pin1 to regulate its nuclear translocation and cellular function
Velusamy Rangasamya,1, Rajakishore Mishraa,1, Gautam Sondarvaa, Subhasis Dasa, et al.
Loyola University Chicago, Maywood, IL 60153;  Beth Israel Deaconess Medical Center, Boston, MA 02115; University of Mississippi Medical Center, Jackson, MS 39216;
University of Wisconsin, Madison, WI 53705; Hines Veterans Affairs Medical Center, Hines, IL 60141; and College of Veterinary Medicine, Iowa State University, Ames, IA 50011
Edited* by Michael Karin, University of California, San Diego School of Medicine, La Jolla, CA, and approved April 11, 2012
Nuclear protein peptidyl-prolyl isomerase Pin1-mediated prolyl isomerization is

  • an essential and novel regulatory mechanism for protein phosphorylation.

Therefore, tight regulation of Pin1 localization and catalytic activity is

  • crucial for its normal nuclear functions.

Pin1 is commonly dysregulated during oncogenesis and likely contributes to these pathologies; The mechanism by which Pin1 catalytic activity and nuclear localization are increased is unknown.
Here we demonstrate that

  1. mixed-lineage kinase 3 (MLK3), a MAP3K family member,
  2. phosphorylates Pin1 on a Ser138 site
  3. to increase its catalytic activity and nuclear translocation.
This phosphorylation event

  1. drives the cell cycle and
  2. promotes cyclin D1 stability and centrosome amplification.

Pin1 pSer138 is significantly

  • up-regulated in breast tumors and
  • is localized in the nucleus.

These findings collectively suggest that the MLK3-Pin1 signaling cascade plays a critical role

  1. in regulating the cell cycle,
  2. centrosome numbers, and
  3. oncogenesis. breast cancer

JNK Peptidyl-prolyl isomerase Pin1 plays a critical role in

  • regulating cellular homeostasis by
  • isomerizing the prolyl bond preceded by
  • a phosphorylated Ser or Thr residue (pSer/Thr-Pro) (1).

This isomerization by Pin1 regulates the biological function of several target proteins, including

  • cell-cycle regulators,
  • protooncogenes,
  • tumor suppressors, and
  • transcription factors (2).
Due to its role in controlling the cell cycle, apoptosis, growth, and stress responses, Pin1 has been linked to the pathogenesis of human diseases, including
  • cancer (3, 4),
  • asthma (5),
  • Alzheimer’s disease (AD) (6), and
  • Parkinson disease (PD) (7).

It is thus quite likely that tight regulation of Pin1 catalytic activity or expression is important for normal physiology. It is reported that Pin1 is

  • overexpressed in most types of cancer (8), whereas
  • its expression is diminished in AD brains (2).

Accumulating evidence suggests that Pin1 isomerase activity

  • and thus function are regulated by posttranslational modifications (2).

Pin1 function is also dependent on its

  • predominant nuclear localization (2),
    • consistent with its substrates being involved in transcription and cell-cycle progression.

It was recently reported that Pin1 nuclear import is regulated by a novel nuclear localization sequence in the PPIase domain, composed of basic amino acids (9). Nonetheless, the detailed mechanism that regulates Pin1 nuclear translocation is still not known. It also remains unknown whether any posttranslational modification of Pin1 can regulate its nuclear translocation or catalytic activity, and therefore directly affect its function.

Stereospecific gating of functional motions in Pin1
Andrew T. Namanjaa, Xiaodong J. Wangb, Bailing Xub, et al.
University of Notre Dame, Notre Dame, IN 46556; Virginia Tech, Blacksburg, VA 24061
Edited by Peter E. Wright, The Scripps Research Institute, La Jolla, CA, and approved June 2, 2011
Pin1 is a modular enzyme that

  • accelerates the cis-trans isomerization of phosphorylated-Ser/Thr-Pro (pS/T-P) motifs
  • found in numerous signaling proteins regulating cell growth and neuronal survival.

We have used NMR to investigate the interaction of Pin1 with three related ligands that include

  1. a pS-P substrate peptide, and
  2. two pS-P substrate analogue inhibitors
    • locked in the cis and trans conformations.

We compared the

  • ligand binding modes and
  • binding-induced changes
    • in Pin1 side-chain flexibility.

The cis and trans binding modes differ, and

  • produce different mobility in Pin1.

The cis-locked inhibitor and substrate produced a

  • loss of side-chain flexibility
    • along an internal conduit of conserved hydrophobic residues,
    • connecting the domain interface with the isomerase active site.

The trans-locked inhibitor

  • produces a weaker conduit response.

Thus, the conduit response is stereoselective. We further show

  • interactions between the peptidyl-prolyl isomerase and
  • Trp-Trp (WW) domains
    • amplify the conduit response, and
    • alter binding properties at the remote peptidyl-prolyl isomerase active site.

These results suggest that

  • specific input conformations can gate dynamic changes that support intraprotein communication.

Such gating may help control the propagation of chemical signals by Pin1, and other modular signaling proteins.

allostery ∣ protein dynamics ∣ ligand dynamics ∣ protein evolution
Phospho-serine/threonine-proline (pS/T-P) motifs are
signaling motifs within
intrinsically disordered loops of cell cycle proteins (1).
The imide bond between the pS/T and P residues can adopt

  • either the cis or trans conformation.

These conformations differ

  • in their susceptibility to kinases and phosphatases

that propagate the chemical signals governing the cell cycle.
Accordingly, the cell must regulate the cis/trans populations of these pS/T-P motifs

  • to ensure proper signal routing.

In this context, the peptidyl-prolyl isomerase Pin1 has emerged as a critical regulator (2, 3). Pin1 is a reversible enzyme that

  • catalyzes the cis-trans isomerization of the pS/T-P imide linkages (2, 3) of other signaling proteins, such as
  1. CDC25C,
  2. p53,
  3. c-Myc,
  4. NF-kB,
  5. cyclin D1, and
  6. tau (3).

Pin1 engages when external events, such as

  • S/T (de)-phosphorylation, change the cis-trans equilibrium.

Pin1 then

  1. catalyzes the cis-trans isomerization, thereby
  2. accelerating the approach to the new equilibrium (1).

Pin1 is a modular protein of 163 residues consisting of a

  • WW domain (1–39) and a larger
  • peptidyl-prolyl isomerase (PPIase) domain (50–163) (Fig. 1).

A flexible linker connects the two domains.

  1. Both domains are specific for pS/T-P motifs (1).
  2. The WW domain serves as a docking module, whereas
  3. catalysis is the sole province of the PPIase domain.

Earlier structural studies of Pin1 revealed

  1. conformational changes upon substrate interaction, thus
  2. motivating flexibility-function studies of Pin1 (4–6).
Peptidyl-prolyl Isomerase Pin1 Controls Down-regulation of Conventional Protein Kinase C Isozymes
JBC Papers in Press, Feb 8, 2012.       http://dx.doi.org/10.1074/jbc.M112.349753

H Abrahamsen, AK O’Neill, N Kannan, N Kruse¶, et al.
From the University of California, San Diego, La Jolla, California 92093
Background: Conventional PKC isozymes have a putative Pin1

  • isomerization sequence at their turn motif phosphorylation site.
Results: Pin1 binds conventional PKCs and

    • promotes their activation-induced down-regulation.
Conclusion: Pin1 isomerizes the phosphorylated turn motif of conventional PKC isozymes,

    • priming them for subsequent down-regulation.
Significance: Pin1 provides a switch regulating the lifetime of conventional PKCs. The down-regulation or cellular depletion of protein kinase C (PKC)
  • attendant to prolonged activation by phorbol esters is a
  • widely described property of this key family of signaling enzymes.

However, neither the mechanism of down-regulation nor whether this mechanism occurs following stimulation by physiological agonists is known.
**the peptidylprolyl isomerase Pin1 provides a timer for the lifetime of conventional PKC isozymes,

  • converting the enzymes into a species that can be dephosphorylated and ubiquitinated
  • following activation induced by either phorbol esters or natural agonists.

The regulation by Pin1 requires both the catalytic activity of the isomerase and the presence of a Pro immediately following the phosphorylated Thr of
the turn motif phosphorylation site,

  • one of two C-terminal sites that is phosphorylated during the maturation of PKC isozymes.
  • the second C-terminal phosphorylation site, the hydrophobic motif, docks
    • Pin1 to PKC.

Our data are consistent with a model in which Pin1

  • binds the hydrophobic motif of conventional PKC isozymes to catalyze the isomerization of the phospho-Thr-Pro peptide bond at the turn motif, thus
  • converting these PKC  isozymes into species that can be efficiently down-regulated following activation.

The peptidyl-prolyl cis-trans isomerase Pin1 is emerging as an important regulator of signal transduction pathways (1).

Pin1-catalyzed isomerization plays a key role in the control of normal cellular functions, most notably proliferation where

    • Pin1 is essential for cell cycle progression (2).

Pin1 belongs to the Parvulin family of peptidyl-prolyl cis-trans isomerases and is the only member that

  • specifically isomerizes phospho-(Ser/Thr)-Pro ((Ser(P)/Thr(P))-Pro) motifs (3):
  1. the enzyme displays an 1000-fold selectivity for peptides phosphorylated on the
  2. Ser/Thr preceding the Pro compared with unphosphorylated peptides (3).
Pin1induced conformational changes in target proteins

  • affect a variety of protein properties from
    • folding to
    • regulation of activity and stability.

As a consequence, deregulation of phosphorylation steps and their attendant conformational changes often lead to disease (4). For example, Pin1 is
downregulated in degenerating neurons from Alzheimer disease patients, correlating with age-dependent neurodegeneration (5).
Pin1 has also been implicated in cancer progression:
levels of this protein are increased in many cancers, including those of the

    • breast,
    • prostate,
    • brain,
    • lung, and
    • colon (6–9).

Thus, Pin1 has been proposed to function as a catalyst for oncogenic pathways (10). The molecular mechanisms that lead to disease progression

  • most likely involve postphosphorylation conformational changes
    • catalyzed by Pin1
    • that are required for downstream effects.
Related articles
The human immunophilin protein FKBP12 colored ...

The human immunophilin protein FKBP12 colored by hydrophobicity (white = hydrophobic) with bound FK506, an immunosuppressant used in treating organ transplant patients to prevent rejection. FKBP also has unrelated prolyl isomerase activity. (Photo credit: Wikipedia)

The human immunophilin protein FKBP12 colored ...

The human immunophilin protein FKBP12 colored by secondary structure with bound FK506, an immunosuppressant used in treating organ transplant patients to prevent rejection. FKBP also has unrelated prolyl isomerase activity. (Photo credit: Wikipedia)

 

 

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Reporter: Prabodh Kandala, PhD

Beta-carotene, selenium and folic acid — taken up to three times their recommended daily allowance, these supplements are probably harmless. But taken at much higher levels as some supplement manufacturers suggest, these three supplements have now been shown to increase the risk of developing a host of cancers.

“It’s not that these nutrients are toxic — they’re essential and we need them, but we need them in a certain balance,” says Tim Byers, MD, MPH, professor of epidemiology at the Colorado School of Public Health and associate director for prevention and control at the University of Colorado Cancer Center.

Byers is senior author of a commentary recently published in the Journal of the National Cancer Institute that discusses the clinical and policy implications of the increased cancer risk from high dose dietary supplements.

“We have a window into less than half of the biology of what these nutrients are doing,” Byers says. “We say generalized things about them, calling them an antioxidant or an essential mineral, but true biology turns out to be more complex than that. The effects of these supplements are certainly not limited to the label we give them. And, as we’ve seen, sometimes the unintended effects include increased cancer risk.”

Currently the FDA regulates dietary supplements as food, but, as Byers and colleagues suggest, supplements, especially at high doses, are more accurately described as inhabiting a mid-ground between food and drugs. Like drugs, supplement ingredients are biologically active — sometimes for better and sometimes for worse

“We need to do a better job as a society in ensuring that the messages people get about value versus risk is accurate for nutritional supplements,” Byers says. “My conclusion is that taking high doses of any particular nutrient is more likely to be a bad thing than a good thing.”

Abstract:

Abstract

Nutritional supplementation is now a multibillion-dollar industry, and about half of all US adults take supplements. Supplement use is fueled in part by the belief that nutritional supplements can ward off chronic disease, including cancer, although several expert committees and organizations have concluded that there is little to no scientific evidence that supplements reduce cancer risk. To the contrary, there is now evidence that high doses of some supplements increase cancer risk. Despite this evidence, marketing claims by the supplement industry continue to imply anticancer benefits. Insufficient government regulation of the marketing of dietary supplement products may continue to result in unsound advice to consumers. Both the scientific community and government regulators need to provide clear guidance to the public about the use of dietary supplements to lower cancer risk.

http://www.sciencedaily.com/releases/2012/05/120515151034.htm

http://jnci.oxfordjournals.org/content/104/10/732

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