Bitter gourd seed fatty acid rich in 9 c,11 t,13 t-conjugated linolenic acid induces apoptosis and up-regulates the GADD45, p53 and PPAR γ in human colon cancer Caco-2 cells

Abstract

Bitter gourd ( Momordica charantia) seed oil (BGO) is a unique oil which contains 9 cis, 11 trans, 13 trans-conjugated linolenic acid (9 c,11 t,13 t-CLN) at a high level of more than 60%. In this study, we investigated the anti-proliferative and apoptosis-inducing effects of free fatty acids prepared from BGO (BGO-FFA) using colon cancer Caco-2 cells. BGO-FFA and purified 9 c,11 t,13 t-CLN remarkably reduced the cell viability of Caco-2. In Caco-2 cells treated with BGO-FFA, DNA fragmentation of apoptosis indicators was observed in a dose-dependent manner. The expression level of apoptosis suppressor Bcl-2 protein was also decreased by BGO-FFA treatment. The GADD45 and p53, which play an important role in apoptosis-inducing pathways, were remarkably up-regulated by BGO-FFA treatment in Caco-2 cells. Up-regulation of PPAR γ mRNA and protein were also observed during apoptosis induced by BGO-FFA. These results suggest that BGO-FFA rich in 9 c,11 t,13 t-CLN may induce apoptosis in Caco-2 cells through up-regulation of GADD45, p53 and PPAR γ.