Effects of Lactobacillus Strains on Colon Cancer Cell Proliferation and Cell Cycle Blockage

Five lactobacillus strains which were obtained from traditional fermented foods in western China, were examined for use as probiotics and for anticancer biological products. The cell walls and cytoplasm extracts from lactobacillus strains were tested for anti-proliferative activity and induction of apoptosis. The results showed the cell walls showed significant direct anticancer activity. 16S rRNA gene sequences of probiotic strains indicated that M5 and X12 were L. paracasei subp. Paracasei, K11 and K14 were Lactobacillus fermentum, X11 was Lactobacillus casei strain respectively. After exposure to the colon cancer cells for 72 h, strong anti-proliferative activity of cell walls from M5, K11 and K14 was efficiently induced through S-phase accumulation in HT-29 cells. Together, these results suggested the cell walls from M5, K11 and K14 to be good probiotic candidates and had potential application in functional products.