Vitamin E-like molecules potentiate the curcumin-induced suppression of Caco-2 cell proliferation

Abstract

We previously reported that curcumin inhibited the proliferation of a human colorectal cancer cell line Caco-2 by both apoptosis and G 2 /M cell cycle arrest. A variety of biological functions of curcumin have been suggested to be involved in its modulatory capacity to oxidative stress. The aim of this study was to investigate the modulation of antioxidants, N -acetyl- L -cysteine (NAC), a-tocopherol (TOC) and trolox, on the suppression of Caco-2 cell proliferation via G 2 /M cell cycle arrest induced by curcumin. NAC (2 mM) reduced the curcumin-induced suppression of Caco-2 proliferation. Inversely, both TOC (0.2 mM) and trolox (0.2 mM) potentiated the curcumin effect. Trolox at the same concentration amplified both G 2 /M cell cycle arrest and p21 elevation induced by curcumin independent of oxidative stress status. These results suggest that Vitamin E-like molecules have the potential to amplify the inhibitory effect of curcumin on Caco-2 proliferation through reactive oxygen species-independent cell cycle modulation, and could offer new insights for preventive measures against colorectal cancer incidence.