Lunasin promotes apoptosis in human colon cancer cells by mitochondrial pathway activation and induction of nuclear clusterin expression

Lunasin is a naturally occurring peptide with arginine-glycine-aspartic acid motif associated to its reported biological activity. We aimed to determine the potential of lunasin from soybean to stimulate apoptosis in HT-29 colon cancer cells. Lunasin caused cytotoxicity to HT-29 cells and induced G2/M cell cycle arrest with simultaneous increased in p21 expression. Lunasin-induced apoptosis as evidenced by a twofold increase in the percentage of cells undergoing apoptosis, decreased Bcl-2:Bax ratio from 8.5 to 0.4, increased caspase-3 activity by 77% and increased expression of pro-apoptotic nuclear clusterin by five fold when compared to untreated cells. In conclusion, lunasin stimulated apoptosis in HT-29 cells by activating apoptotic mitochondrial pathways and inducing expression of the pro-apoptotic nuclear clusterin.