High-Fiber Foods Block Cancer PathwaysFebruary 26, 2010
Why do people who eat high-fiber diets typically have lower incidence of certain cancers? Researchers at the Univ. of Colorado Cancer Center may have an explanation after discovering that a nutrient called inositol hexaphosphate (IP-6) blocks a pathway some cancer cells use to multiply, recruit blood vessels and keep from dying. IP-6, also commonly known as phytic acid, is found in high concentrations in whole grains and legumes. It’s also a currently available nutritional supplement. Mallikarjuna Gu, a research associate of Pharmaceutical Sciences Dept. at the Univ. of Colorado School of Pharmacy, discovered that treating prostate cancer cells in a Petri dish and those transplanted into mice with IP-6 stopped the cancer from growing. Upon further investigation, he discovered that IP-6 disrupts the P13K-Akt pathway, which is shown to play a major role in the development and progression of prostate cancer, breast cancer and colorectal cancer. “P13K-Akt is a master regulator of carcinogenesis,” Gu says. “It’s a cascade pathway, so if we can block its action, we stop many processes from starting. We showed that IP-6 inhibits the pathway not only in cells, but also in mice transplanted with human prostate cancer cells. That’s very exciting news, because in cancer we are looking for targets. We found a major target.” Gu works in the lab of Rajesh Agarwal, co-leader of UCCC’s AMC Cancer Prevention and Control Program and professor of Pharmaceutical Sciences at the Univ. of Colorado School of Pharmacy. Agarwal studies natural substances that can prevent cancer from happening or keep it from returning once treatment is complete. Agarwal says the research points out how IP-6 works in cells, and may explain why people who eat diets high in fiber—and specifically high in legumes—seem to have a lower risk of cancer. “If IP-6 blocks the mechanism that certain cancers use to stay alive, it makes sense that people who eat a lot of it would block that same mechanism,” Agarwal says. “Now, we have to do clinical trials to find out how much IP-6 is needed to have both preventive and therapeutic effects.” Agarwal is collaborating with UCCC prostate cancer physicians Michael Glodé and Thomas Flaig to design clinical trials of various natural products, to test how they work in men with prostate cancer or signs they may develop it. “We may see if we can alter the speed of prostate cancer development in men who are at high risk by giving them this supplement or having them change to a diet high in fiber and legumes,” Agarwal says. “And we may also explore combining IP-6 with traditional chemotherapy to see if we can get a synergizing effect—if the supplement makes the cancer drugs work better.” The discovery is published in Cancer Research. Source: Univ. of Colorado Cancer Center
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