Anti-tumor potential of cell free culture supernatant of Lactobacillus rhamnosus strains isolated from human breast milk

Lactobacilli rhamnosus has been characterized as a probiotic and plays an important role in human health by stimulating the supplement of nutrients, preventing the colonization of pathogens, and influencing the immune system. This study investigated the anticancer activity of the three Lactobacillus rhamnosus strains SHA111, SHA112, and SHA113 isolated from human breast milk. The cell-free supernatant of a liquid culture of the three strains showed excellent antioxidant activities against DPPH free radicals, superoxide anion radicals, and hydroxyl radicals; furthermore, significant anticancer activity was found on cervix cancer cells (HeLa) via cytotoxicity and induction of apoptosis. RT-qPCR and western blot analysis showed the induction of apoptosis was achieved via the up-regulation of BAD, BAX, Caspase3, Caspase8, Caspase9, and down-regulation of BCL-2 genes in HeLa cells. The results suggest that these strains have potential anticancer capability.