Green Tea, Glycine May Slow Tumor Growth

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http://content.health.msn.com/content/article/1728.92741Green Tea, Glycine May Slow Tumor GrowthMore Evidence for Anti-Cancer Benefits of Common Food ChemicalsBy Salynn BoylesNov. 2, 2001 -- You've probably read that green tea appears to protectagainst cancer. You may even know that its anti-cancer properties areattributed to an abundance of chemicals called polyphenols. But new researchmay explain, for the first time, how those chemicals fight tumors at amolecular level.Using prostate cancer cell lines, researchers from H. Lee Moffitt CancerCenter in Tampa, Fla., found that polyphenols in green tea, and black andred teas for that matter, target a protein known to protect cancer cellsfrom death. The research, along with several other studies evaluating theanti-tumor properties of food components, was presented this week at aninternational conference in Miami Beach, Fla.The amino acid glycine was found to reduce breast tumor growth in rats.Apparently, it blocks the growth of new blood vessels that feed tumors.Glycine is manufactured in the body, but is also commercially available as adietary supplement."These are very preliminary studies, but they are quite interesting,"American Association for Cancer Research (AACR) President Waun Ki Hong, MD,tells WebMD. He says that human studies are needed to verify the findings,but this may represent an important contribution to the research. AACRco-sponsored the annual meeting along with the National Cancer Institute andthe European Organization for Research and Treatment of Cancer.In the green tea research, Aslamuzzaman Kazi, PhD, and colleagues found thatpolyphenols reduced the level of Bcl-XL protein in prostate cancer celllines. Bcl-XL has been shown to protect cancer cells from death -- knownscientifically as apoptosis"The higher the concentration [of polyphenols] the more apoptosis," Kazitells WebMD. "Epidemiological studies have shown that tea has anticanceractivities. We wanted to try to understand the molecular mechanism of thisaction."Studies in humans have, in fact, been inconclusive regarding the role of teain preventing or slowing cancers. While some have shown a clear protectivebenefit, others have not. The most recent large study, published last Marchin The New England Journal of Medicine, found that drinking green tea didnot lower the risk of developing stomach cancer in a group of Japanesesubjects.In the glycine study, researcher Zishan Haroon, MD, PhD, and colleagues atDuke University Medical Center, found high levels of glycine reduced breasttumor growth rates by 15% in rats by blocking the growth of newtumor-feeding blood vessels. The special diet also reduced wound-healing by30%, which, Haroon tells WebMD, explains glycine's effect on tumors."Tumors and wounds have one very important thing in common -- they bothproduce new blood vessels through the same mechanism, known asangiogenesis," he says. If you can block one response, you can block theother, he says.© 2001 WebMD Corporation. All rights reserved.