Showing posts sorted by relevance for query telomerase inhibitors. Sort by date Show all posts
Showing posts sorted by relevance for query telomerase inhibitors. Sort by date Show all posts

Saturday, October 10, 2009

Telomerase & Telomerase inhibition.......

When I read about the Nobel prize in Medicine, was really excited because the scientists who discovered the enzyme telomerase got the Nobel prize for the year 2009 and the reason for this is simple and obvious....

When I was working with my previous company (Innovasynth Technologies Limited, Khopoli), I had opportunity to learn lots of things (from Dr. Sergei Gryaznov of Geron Corporation) about the drugs with Telomerase inhibition activity. As for as my knowledge goes, there are many companies working on these class of compounds and hope in the days to come there will be many drugs from this class of compounds and antisense drugs.

About Telomerase :

Telomerase, is an enzyme that adds specific DNA sequence repeats to the 3' end of DNA strands in the telomerase regions, which are found at the ends of eukaryotic chromosomes. The telomeres contain condensed DNA material, giving stability to the chromosomes. The enzyme is a reverse transcriptase that carries its own RNA molecule. Though the existence of a compensatory shortening of telomere (telomerase) mechanism, was first predicted by Soviet biologist Alexey Olovnikov (1973), who also suggested the Telomere hypothesis of ageing and the Telomere relations to cancer. Carol Greider and Elizabeth Blackburn in 1985, discovered telomerase together with Jack Szostak. Greider and Blackburn have been awarded the Nobel Prize in Physiology or Medicine. Congrats for this remarkable achievement.


Telomerase inhibitors :

To safeguard against cancer, adult cells keep track of how many times that they have multiplied, and once they have reached a pre-set limit — often around 80 divisions — they die. Telomerase interferes with this record keeping. So if one can find a drug or gene therapy that interferes with telomerase, it could fight the unchecked growth of cancer cells. As per the claim by lead researcher (Mark Muller), 90% all cancer cells are telomerase rich. Geron corporation, is developing modified DNA molecule (for which Innovasynth, has tie up with Geron to provide the intermediate amidites). The oligonucleotides, which target the template region, or active site, of telomerase. Geron's work has focused oligonucleotides (GRN163 and GRN163L,) and as per the claim by the company, both of them have demonstrated highly potent telomerase inhibitory activity at very low concentrations in biochemical assays, various cellular systems and animal studies. Interestingly these compounds are direct enzyme inhibitors, not antisense compounds and smaller than typical antisense compounds or other oligonucleotide drug candidates. Both compounds use a special thiophosphoramidate chemical backbone and the company is hopeful of convincing clinical trial results. All the best...

Ref : 1. http://nobelprize.org/nobel_prizes/medicine/laureates/2009/press.html
2. http://www.geron.com/products/productinformation/cancerdrug.aspx

Wednesday, May 8, 2013

New potential target for cancer therapy identified

In continuation of my update on telomerase...




The enzyme telomerase is overexpressed in almost all cancer cells, and previous research efforts have failed to identify good telomerase inhibitors. The study by Dr. Woodring Wright and UT Southwestern colleagues in the April 4 issue of Cell Reports identifies a new approach for inhibiting telomerase, which is an enzyme that drives uncontrolled division and replication of cancer cells.
Alternative splicing allows genetic information to be assembled in different ways and is almost always controlled by DNA sequences that are immediately adjacent to the parts of a gene that code for protein. "In the case of the telomerase gene, we found that these controlling regions are located very far from the protein coding regions and that they contain unusual DNA sequences," said Dr. Wright, professor of cell biology and internal medicine. "Their unusual DNA structure suggests that humans regulate telomerase in a very different fashion that we may be able to exploit to develop inhibitors of the enzyme."
Most of the splice variants that telomerase makes are inactive, but Dr. Wright's team demonstrated that it was possible to shift the splicing to make even less active telomerase, potentially providing a new approach for cancer therapy....


New potential target for cancer therapy identified

Friday, January 8, 2010

Imetelstat (GRN 163L) shows promising results against brain cancer glioblastoma and prostate cancer...

In continuation of my update on Telomerase inhibitors, I find this info really interesting and hence sharing here with. As mentioned in my earlier blog about imetelstat (GRN163L )  has been undergoing Phase I clinical trials designed to examine the safety, tolerability, pharmacokinetics and pharmacodynamics of the drug, alone or in combination, in solid tumors, chronic lymphoproliferative disease, multiple myeloma, lung and breast cancers and the company claims that Phase I objectives for imetelstat  (structure) have been achieved. Now  Dr. Jerry Shay, professor of cell biology of  The University of Texas Southwestern Medical Center at Dallas, claims that the same drug shows promise in fighting the brain cancer glioblastoma and prostate cancer.

Glioblastomas are the most common malignant brain tumors in adults, according to the American Cancer Society. They are difficult to treat with drugs because blood vessels in the brain have tightly constructed walls that allow only a few substances to pass through.

The researcher focused on cells called tumor-initiating cells. Some researchers believe that tumors contain a small subset of initiating cells – or cancer stem cells – that are able to initiate and drive tumors and that are often resistant to radiation therapy and chemotherapy.

In the glioblastoma study, Dr. Shay and his colleagues found that imetelstat blocked the action of telomerase in isolated tumor-initiating cells as well as the bulk of the tumor cells, eventually killing the cells. Combining imetelstat with radiation and a standard chemotherapy drug made imetelstat even more effective. When the researchers implanted human tumor-initiating cells into rodents, they found that imetelstat was able to enter brain tissue and inhibit telomerase activity.

In the prostate cancer study, the researchers isolated tumor-initiating cells from human prostate cancer cells. The cells showed significant telomerase activity. Imetelstat blocked the enzyme’s activity, and telomeres shortened greatly. As per Dr.Shay, since the drug attacks a mechanism that is active in most cancers, it might prove to be widely useful, especially when combined with other therapies.

Hope  Geron people must be really happy for these results  and conclusions.....

Ref : http://www.utsouthwestern.edu/utsw/cda/dept353744/files/570509.html