Drug resistance is one of the major problems, which causes recurrence of cancers. Therefore, complementary treatments are needed to improve the impacts of chemotherapy agents. The effect of probiotics as cancer-preventing agents through involvement in the activation of apoptotic pathways has been established. The present study sought to investigate how the heat-killed form of Saccharomyces cerevisiae (as a probiotic) could affect the Akt/NF-kB-induced apoptosis in colon cancer cells, the SW480 cell line. The cytotoxic effects of heat-killed yeast (HKY) and 5-fluorouracil (5-FU, as a positive control drug) were assayed using the MTT method. Morphological changes followed by apoptosis were examined using DAPI staining. The transcription and translation level of apoptosis genes were explored with qRT-PCR and western blotting. The data were analyzed using GraphPad Prism V6.0 Software. The results showed that HKY could induce apoptosis in colon cancer cell line through downregulation of p-Akt1, Rel A, Bcl-XL, pro-caspase 3, and pro-caspase 9 expressions, and upregulation of BAX, cleaved caspase-3, and cleaved caspase-9. Besides, Akt protein expression was not affected. It is noticeable that HKY had a better modulating effect on BAX expression compared with 5-FU. It was able to modulate Akt/NF-kB signaling pathway followed by the apoptotic cascade.
Keywords: Akt/NF-kB signaling pathway; Apoptosis; Colorectal cancer; Probiotics; Saccharomyces cerevisiae.