Survivin Inhibition Is Critical for Bcl-2 Inhibitor-Induced Apoptosis in Hepatocellular Carcinoma Cells

Our study aims to study the therapeutic effects of a novel Bcl-2 inhibitor, ABT-263, on hepatocellular carcinoma (HCC) and to provide primary preclinical data for future clinical trial with ABT-263. In this study we showed that Bcl-xL and survivin were up-regulated in HCC cell lines and human liver cancer tissues. Clinic used ABT-263 single treatment had no apoptotic effects on HCC cells whereas higher doses of ABT-263 did. Interestingly, the combination treatment of ABT-263 with survivin inhibitor YM-155 could result in significant apoptosis in HCC cells. Survivin inhibition through gene silencing significantly enhanced ABT-263 to induce apoptosis in HCC cells. We found that low dose of ABT-263 single treatment resulted in ERK activation and survivin up-regulation, which might be involved in the resistance of HCC cells to ABT-263 since blockade of ERK activation sensitized ABT-263-induced apoptosis. Importantly, ABT-263 and YM-155 combination treatment had no apoptotic effects on normal human hepatocytes. Taken together, these data suggest the combination treatment of Bcl-2 inhibitor and survivin inhibition may have a great potential for liver cancer therapy.