Lactobacillus in cancer therapy

Abstract

Colon cancer is the second most common cancer in developed countries, as well as in Singapore. This study demonstrated that both Lactobacillus rhamnosus strain GG (LGG) and Lactobacillus casei strain Shirota (LcS) but not Lactobacillus bulgaricus (control bacteria) exerted specific dose dependent anti-proliferative effects on colon carcinoma cells. The results suggest that the anti-proliferative effects of LGG and LcS were due to their pro-apoptotic effects in colon carcinoma cells which were decreased in the presence of streptomycin. Experimental data indicated that nitric oxide production was not the cause of cytotoxicity. Cell-bacteria contact was also not necessary for the induction of anti-proliferative effects by lactobacilli, suggesting the presence of soluble cytotoxic mediators. There was absence of lactobacilli-induced interleukin-8 mRNA expression but increased protein secretion by colon carcinoma cells. This data indicates that commonly consumed lactobacilli can differentiated between normal and cancerous cells.