Curcumin inhibits the proliferation and induces apoptosis in HT-29 cell lines through a reactive oxygen species (ROS)-dependent mechanism

Curcumin, a natural pigment extracted from Curcuma longa, has anti-carcinogenic activities in many cancer cell lines. The molecular mechanism of apoptosis induced by curcumin are still unknown. In the current study, we investigated the roles of reactive oxygen species in curcumin stimulated apoptosis in HT-29 cells. Curcumin significantly reduced cell viability, induced apoptosis, activated caspase-3 activity and stimulated concentration-dependent release of ROS. Inhibition of ROS generation by scavengers suppressed apoptosis and Bcl-2 expression induced by curcumin, indicating the critical roles of ROS in the apoptotic process. However, caspase-3 inhibitor (z-VAD-FMK) couldn't completely inhibit the curcumin induced apoptosis, indicating ROS mediated apoptosis may be caspase-independent. Together, our findings showed that ROS played significant roles in the apoptosis induced by curcumin in HT-29 cells.