Possible molecular mechanisms and pathways involved in BH3 mimetic activity of alpha-lipoic acid on human colon cancer cell line

Abstract

Alpha-lipoic acid (ALA), a naturally-occurring antioxidant, inhibits proliferation and induces apoptosis in various cancer cell lines without effects on normal non-transformed cells. The aim of this study was to examine the effects of alpha-lipoic acid (ALA), alone and combined with 5-fluorouracil (5-FU), on Bcl-2/Bax expression in human colon cancer Caco-2 cell line as well as to investigate possible molecular mechanisms and pathways involved in ALA-mediated effects. In the present study ALA and 5-FU showed a tendency to decrease Bcl-2 and increase Bax expression. ALA exerted higher inhibitory effects on Bcl-2 expression, while the significant increase of Bax expression was shown after the treatment with the combination of ALA and 5-FU. The binding modes of ALA and 5-FU with both targets were shown to be closely similar, and some interactions the same like those of known BH3 mimetics. Thus, ALA may be considered as potential BH3 mimetic. Additionally, with in silico calculated physico-chemical properties taken into account, it was confirmed that ALA may easily be delivered to its intracellular and membrane targets.