The prophylactic effect of probiotic Bacillus polyfermenticus KU3 against cancer cells

Bacillus polyfermenticus KU3 was isolated from kimchi, a Korean dish made from fermented vegetables and its potential probiotic characteristics were investigated. The spore cell of B. polyfermenticus KU3 was highly resistant to artificial gastric juice and survived for 24 h in artificial bile acid. B. polyfermenticus KU3 did not generate the carcinogenic enzymes, β-glucosidase, N-acetyl-β-glucosaminidase, and β-glucuronidase, and adhered strongly to HT-29 human intestinal epithelial cell lines. Using the [3-4,5-dimethylthiazol-2-yl]-2,5-diphenyletrazolium bromide assay, we found that B. polyfermenticus KU3 strongly inhibited the proliferation of cancer cells such as HeLa, LoVo, HT-29, AGS, and MCF-7 cells. The supernatant of B. polyfermenticus KU3 had an anticancer effect against HeLa and LoVo cells. Conversely, the proliferation of normal MRC-5 cells was not inhibited. We also demonstrated the anti-inflammatory activity of B. polyfermenticus KU3 under inflammatory conditions, as shown by the reduction in nitric oxide and proinflammatory cytokines (TNF-α, IL-10, TGF-β2, and COX-2). These results demonstrate the probiotic characteristics of B. polyfermenticus KU3 and provide evidence for the effect of this bacterium against various cancer cells.