Targeting Prostate Cancer With Stem Cells
“Prostate cancer will kill more than 32,000 American men this year alone, and the death rate is twice as high in African Americans,” says John T. Isaacs, Ph.D., The R. Christian B. Evensen Scholar. While early detection and better treatment have saved thousands of lives, science still has far to go in fi ghting cancer that has been detected at an advanced state, or high-risk cancer that is likely to return after initial treatment. This is the cancer that Isaacs has spent his career working on ways to stop.
“The long-term goal of our lab is to develop effective therapies to prevent death from this devastating disease,” says Isaacs, who has developed three drugs that are currently in clinical trials for patients with prostate cancer. One of these is an angiogenesis inhibitor, discussed here , a drug that slows down cancer by interfering with its ability to make new blood vessels. Now Isaacs is looking at a different way to target cancer that has spread to distant sites in the body: Stem cells. These cells, extracted from bone marrow, have the potential to kill lethal cancer cells without touching normal cells just a hairbreadth away. “This approach is based upon the fact that mesenchymal stem cells, which come from adult bone marrow, travel through the bloodstream and eventually stop at sites of prostate cancer, drawn by the presence of certain chemicals made by the cancer cells,” says Isaacs. He takes these cells, found in the bone marrow of healthy donors, and makes more of them in the laboratory. Then, using molecular techniques, “we induce these cells to produce and secrete a protein, which is engineered so that it can only be activated to kill prostate cancer cells.” These specially formulated stem cells will then be put back in the patient’s blood, where they will travel to areas where prostate cancer has metastasized. “The hope is that they will act as ‘Trojan Horses’,” says Isaacs, “killing prostate cancer while preventing unwanted side effects in normal tissue.”