Health Watch -- Anti-cancer Enzymes

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Blocking an enzyme that keeps cells from dying naturally may help make cancer treatments more effective.

Cells come with their own built-in timers that determine their life cycles. These are called telomeres, and they’re sequences of repeating DNA that get shorter as cells age. But in cancer cells, an enzyme called telomerase keeps telomeres from functioning so that the cells don’t die properly and instead keep growing out of control. Cancer researchers believe that stopping telomerase may be a key to killing cancer cells, but most studies have found that it takes months of treatment before tumor growth slows.

Now some researchers at UT Southwestern Medical Center at Dallas have found a more effective way to fight cancer by stopping telomerase activity. In laboratory studies, their telomerase inhibitor compound slowed cancer cell growth in only a few weeks. This inhibitor also stopped prostate cancer cells from growing into tumors in mice. Mice treated with the telomerase inhibitor had low PSA levels, which are a sign of cancer.

Dr. David Corey, the UT Southwestern researcher who led the study, says that the inhibitor was even more effective when combined with other cancer treatments. After the original tumor is removed through surgery, radiation or chemotherapy, the telomerase inhibitor appears to keep tumors from coming back. Most cancer patients die when their cancer returns after the initial treatment, so this new therapy could make a big difference in saving lives.