Prevention of colorectal cancer development by Bio-K+ probiotic formula

点击翻译按钮获取中文摘要

Colon cancer is one of the leading causes of morbidity and mortality, not only in Western industrialized countries but also in developed Asian countries. Currently, colorectal cancer (CRC) is the 2nd leading cause of cancer death in Canada (after lung cancer). The most recent estimated statistics for CRC for 2009 are: 22,000 new cases and 9,100 deaths. Estimated CRC deaths in Canada in 2009 are 9,100 (Canadian Cancer Society). Therefore, prevention of cancer in generally and colon cancer in specifically is very important. The use of probiotic bacteria in cancer chemoprevention is an active preventive strategy to inhibit, delay or reverse human carcinogenesis. Some studies have proposed that microbial cell wall components from probiotic bacteria (ex: bacterial peptidoglycans) could be responsible of cancer prevention. However, no study have been done to confirm this hypothesis and to elucidate their mechanisms in cancer prevention. In an in vitro anti-proliferative test against colon cancer cell line, it was found that there was a synergistic effect of Bio-K+® bacterial strains with 5-Fluorouracil in enhancing the apoptosis in a colon cancer cell line. In another research on in vivo prevention of aberrant crypt foci (ACF) formation in rats treated with a carcinogen, Bio-K+® fermented milk was demonstrated to be able to reduce significantly the formation of ACF (a precancerous lesion in rat intestine and related to colon cancer). Based on our recent research, we suppose that BioK+® fermented milk at an optimized dose will have a strong in vivo activity in prevention of aberrant crypt foci (ACF) formation in rats treated with a carcinogenic agent. It is also supposed that bioactive components produced by probiotic strains during milk fermentation to produce Bio-K+® products may be the main components in reduction of ACF formation in rats. The objectives of this work are 1) to investigate the dose-effects of BioK+® fermented milk in reducing precancerous lesions in in vivo test and 2) to fractionate bioactive compounds from BioK+® fermented milk and evaluate their effects in reducing precancerous lesions in in vivo test.