Curcumin sensitizes lung cancer cells to cisplatin-induced apoptosis through superoxide anion-mediated Bcl-2 degradation.

The purpose of this study was to investigate the sensitizing effect of curcumin on cisplatin-induced apoptosis in non-small cell lung cancer (NSCLC) H460 cells. Curcumin was shown to induce superoxide anion generation, down-regulate anti-apoptotic Bcl-2 protein, and subsequently sensitize cells to cisplatin-induced apoptosis. Co-treatment of the cells with curcumin and cisplatin resulted in increased apoptosis and reversal of Bcl-2-mediated cisplatin resistance. The mechanism by which curcumin down-regulates Bcl-2 and sensitizes cells to cisplatin-induced apoptosis involves proteasomal degradation of Bcl-2. These findings indicate a novel pathway for curcumin regulation of Bcl-2, which could benefit the development of a cisplatin sensitizing agent.