Secreted Chemicals From Probiotic Bacteria Potentiate Th1 Pattern of Immune Cells and Apoptosis Induction in Breast Cancer and Gastric Adenocarcinoma Cell Lines

Cancer is one of the main causes of mortality. Therapeutic importance in some diseases, especially cancers has led to considering the anti-cancer effects of probiotics more than ever. Probiotics have stimulatory effects on the immunity and suppressor effects on cancer activity. Various studies report that probiotic bacteria have cytotoxicity effects on different types of solid tumors. In this research, we evaluated the synergic effect of secretory chemicals of Lactobacillus and Bifidobacterium bacteria on cytotoxic potency of breast and gastrointestinal cancer cell lines. Bifidobacterium bifidum and Lactobacillus acidophilus were cultured in MRS broth. Cytotoxicity assay was performed on AGS, MCF-7 cell lines, and peripheral mononuclear cells after treatment with bacteria extractions by MTT test. β-actin, Bcl2, Bax, TNF-α, and IFN-γ gene expression levels were evaluated in treated cell lines by real-time PCR method. The result of cytotoxicity assay showed that the obtained extraction from the bacterial cultures has a higher killing effect on cancer cells compared with normal cells. Results of gene expression indicated a significant increase in Bax and Bcl2 gene expression in cancer cells. TNF-α gene expression increased significantly as compared with the control group. The obtained extraction from probiotics culture can induce death in cancer cells through the apoptosis mechanism and improve the cellular immune response, i.e., T helper 1 cytokine profile.