Discovered: How Omega-3 Fatty Acids Cut Cancer Risk. For years, scientists have recognized that nutrients known as omega-3 fatty acids, which are commonly found in fish oil, offer significant protection against colon cancer. Now, researchers at the University of Texas Medical Branch at Galveston (UTMB) have figured out how these compounds tend to keep the colon cancer-free -- a discovery that may also have implications for prevention and treatment of many other kinds of cancer. The reason, according to a paper the UTMB scientists published June 10 in The Journal of Cell Biology, is that omega-3 fatty acids block the action of a chemical called protein kinase C beta II (PKCbII), which is associated with increased vulnerability to colon cancer. "If you give a cancer-causing agent to animals, what you see is that the cells start proliferating more, and in common with that we see an increase in PKCbII expression," says Alan P. Fields, director of UTMB's Sealy Center for Cancer for Cancer Cell Biology and senior author of the paper. "If you feed the animals an omega-3 fatty acid you blunt that proliferative response. "The hypothesis was that PKCbII caused hyperproliferation and increased sensitivity to carcinogens, and that it was the target for the omega-3 fatty acid," he adds. To test that hypothesis, Fields and Nicole R. Murray, lead author of the paper, created genetically modified mice whose colon cells over-produced PKCbII. These transgenic rodents were far more likely to develop colon cancer when exposed to a known carcinogen than were normal mice, and they showed evidence of the runaway cell growth that precedes cancer even when not exposed to any carcinogen. Giving transgenic mice a diet high in omega-3 fatty acids, however, reduced their chance of colon cancer to that of normal mice, and these mice also exhibited no runaway growth of colon cells. "We found that the hyperproliferation, which we normally see in these transgenic animals, is completely blocked by omega-3 fatty acids," Fields says. "And furthermore, now when we expose these animals to a carcinogen, they have the same cancer risk as non-transgenic mice." In addition to determining that omega-3 fatty acids inhibit the cancer-causing action of PKCbII in mice, the scientists also used cultures of cells taken from rat intestines to find out just how PKCbII causes the hyperproliferation of cells that can lead to cancer. Cells with a high level of PKCbII, they found, produced much less of a substance known as transforming growth factor beta receptor type II (TGFbRII), a molecule critical to keeping cell reproduction under control. Examination of colon cells from the PKCbII transgenic mice not given omega-3 fatty acids revealed that they, too, lacked TGFbRII -- but colon cells from transgenic mice fed omega-3 fatty acids had the receptors in abundance. "Just as in the cell lines in which we over-expressed PKCbII and the TGFbRII levels were suppressed, we saw the same effect in our transgenic mice," Fields says. "But then when we fed them an omega-3 fatty acid diet, we inhibited PKCbII, and TGFbRII levels came back up. So there's a reversal in this high-risk animal." Fields points out that low levels of TGFbRII also have been observed in many other cancer cell types, including breast cancer, gastric cancer, small-cell lung cancer, esophageal cancer, liver cell carcinoma, bladder cancer, squamous cell carcinoma, endometrial cancer and osteosarcoma. Taken together with the observation that omega-three fatty acids also seem to protect against breast and prostate cancer, he notes, this suggests that PKCbII may play a significant role in more than just colon cancer -- and that inhibiting its action, either through diet or drugs, could help prevent and treat a broad range of diseases. "Protein kinase C bII and TGF bRII in w-3 fatty acid-mediated inhibition of colon carcinogenesis," by Nicole R. Murray, Capella Weems, Lu Chen, Jessica Leon, Wangsheng Yu, Laurie A. Davidson, Lee Jamieson, Robert S. Chapkin, E. Aubrey Thompson and Alan P. Fields, appears in The Journal of Cell Biology, Volume 157, Number 6, June 10, 2002. June 13, 2002 Thanks to Alternative Health News Online www.altmedicine.com Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.