Abstract:
Kefir is a fermented milk product, to which many health benefits have been attributed. These
include anti-microbial, anti-inflammatory, immunomodulatory, and metabolic benefits. Most
importantly, many studies have proven that kefir may have anti-cancerous potential. The current
study aims at examining the effect of this probiotic on colorectal cancer cells, in vitro. Kefir’s
anti-cancer potential was tested on Caco-2 and HT-29, colorectal adenocarcinoma cell lines,
through cytotoxicity, proliferation, and apoptotic assays. Kefir’s cytotoxicity was assessed by
determining the percentage viability of cells, using the Trypan Blue Exclusion method. After
determining the IC50, the effect of various concentrations of kefir on the proliferation of Caco-2
and HT-29 cells was determined. Using WST-1 cell proliferation assay, kefir was shown to be
anti-proliferative to the cells in a dose and time dependent manner. Through flow cytometry,
kefir was also shown to induce cell cycle arrest at the G1 phase, which was assumed to be an
apoptotic effect. This was then confirmed by Cell Death Elisa Plus kit, which showed that
apoptosis increased with increasing kefir concentration. Western Blot analysis demonstrated that
kefir induces the overexpression of Bax, while repressing Bcl-2.
