Yeast Extract Induces Apoptosis and Cell Cycle Arrest via Activating p38 Signal Pathway in Colorectal Cancer Cells.

The microbiome has recently become a key interest for cancer research. Anti-tumor effects of reinforced clostridium media (RCM) were investigated for all ingredients of RCM, which showed that yeast extract could be a candidate for this phenomenon. MTT assay, cell counting, cell death analysis, cell cycle analysis, and Western blotting were done on colorectal cancer cells with or without 5-fluorouracil resistance (SNU-C5 and SNU-C5/5-FUR). Yeast extract treatment showed dose- and time-dependent anti-tumor effects on SNU-C5 and SNU-C5/5-FUR. Anti-tumor effects were related to G0/G1 phase arrest with increased p21, reactive oxygen species scavenger activities, and decreased free iron. Yeast extract treatment significantly increased apoptosis, which was effectively blocked with the PARP inhibitor. Anti-tumor effects of yeast extract were correlated with the increased phosphorylation of p38 and p53. These results suggest that yeast extract might inhibit the proliferation of colorectal cancer cells via the activation of the p38-p53-p21 cascade.