Can a telomerase inhibitor effectively treat prostate cancer?
Posted Jan 04 2010 12:00am
New animal research has suggested that the telomerase inhibitor imetelstat may have activity in the treatment of prostate cancer.
Pieces of DNA called telomeres are important in helping to control how often cells divide. Telomeres are like protective “caps” of DNA on the ends of chromosomes. Chromosomes are the parts of cells into which a person’s genes are “packed.” Humans have 46 of them. If the telomeres are longer than a particular minimum length, a cell can keep dividing. But telomeres shorten each time a cell dividees in two, so a cell stops dividing once the telomeres reach a certain minimum size, … BUT … in cancer cells an enzyme called telomerase keeps rebuilding the telomeres. What’s the result? Well, in the first place the cancer cells never receive the a message that they’re meant to stop dividing; so, in the second place, to all intents and purposes the cancer cells go on dividing ad infinitum — they become “immortal.”
Imetelstat is a drug that has been shown to inhibit the actions of telomerase under certain, well-defined circumstances. And in a recent study, Marian et al. have shown that imetelstat can inhibit the activity of telomerase enzymes in the so-called “tumor initiating cells” that are associated with the early growth of prostate cancer and the spread of prostate cancer to other parts of the body. In particular, imetelstat is know to prevent the activity of telomerase in some cancer cells that lie dormant in the bone marrow (and we know that such dormant cancer cells can occur in prostate cancer patients, although we don’t know exactly how prostate cancer cells get to the bone marrow).
It is certainly much too early to know whether this research will produce an active drug for prostate cancer prevention or treatment, but this would represent a very different mechanism of action on a very different drug “target” related to management of prostate cancer, so we will be following this research with interest. According to a media release issued by the University of Texas Southwestern Medical Center, imetelstat is also being studied in at least three other forms of cancer.