Laetiporus sulphureusmushroom extract strongly enhances proapoptotic effect of probiotics Bifidobacterium lactison HCT-116 cells in a co-culture system

Laetiporus sulphureusis an edible mushroom with significant medicinal potential due to its rich polyphenol composition. Complete activity of polyphenols in the colon depends on the probiotic bacteria which already demonstrated proapoptotic effects on colon cancer cells. Our study uses a simple HoxBan co-culture system in order to approximate real in vivoconditions. Present study examined for the first time the cytotoxic effect of L. sulphureusethyl acetate extract (EALS) and Bifidobacterium animalissubsp. lactis(BAL) probiotic on colorectal (HCT-116) and healthy (MRC-5) cells. EALS, abundant in polyphenolics detected by HPLC, showed weak cytotoxic activity (MTT assay) on HCT-116 and MRC-5 cells. Strong cytotoxicity of BAL and BAL/EALS on HCT-116 cells (determined by trypan blue staining and flow cytometry) was due to induction of pro-apoptotic effects. External apoptotic pathway was activated viaintensified expression of Caspase 8and Caspase 3, detected by qPCR method. The results show that EALS strongly enhances the cytotoxic and pro-apoptotic effects of BAL on HCT-116 cells in the co-culture system. Directions for future research are suggested to ultimately provide the clarification whether the structural change of polyphenols caused by the activity of BAL, or the change in the metabolic activity of BAL by polyphenols, are responsible for exact mechanism of these treatments activity. Also, the consequences of direct contact of BAL and HCT-116 cells should be further examined in appropriate in vivosystems.