RESUMEN
Abstract This study highlights the cytotoxic effect of three L. casei strains on colorectal cell lines in invitro conditions. Different concentrations of live, heat killed (HK) and cell free supernatant (CFS) of three L.casei strains were subjected to CaCo2 and MRC5 cell lines. The viability of the treated and untreated cells was determined after 72 hrs by MTT assay, and IC50 estimated. Apoptosis was evaluated by Annexin V-propidium iodide method using flow cytometry. The live, HK and CFS of the L. casei strains showed cytotoxic effects on colorectal cell lines with significant differences. The cytotoxicity effects of live cells on CaCo2 cells were significantly higher (pË0.01) than the HK cells. A dose dependent response was observed, as higher concentrations resulted in enhanced cytotoxicity effects. Live L.casei 1296-2cells inhibited 91% of CaCo2 cell growth, with IC50 of less than 108 cfu/ml. MRS medium and concentrations of CFS at above 20% v/v, were cytotoxic to the normal cell lines. Flow cytometry analyses of L. casei 1296-2 indicated that cytotoxicity effects on CaCo2 cells is related to apoptotic induction. Invitro studies indicate that Live and CFS of L. casei 1296-2 might be promising candidate for the control of colorectal cancers