Abstract
Hepatocellular carcinoma (HCC) is one of the most common and deadly human cancers. The 5-year survival rate is very low. Unfortunately, there are few efficacious therapeutic options. Until recently, Sorafenib has been the only available systemic drug for advanced HCC. However, it has very limited survival benefits, and new therapies are urgently needed. In this study, we investigated the anti-HCC activity of carfilzomib, a second-generation, irreversible proteasome inhibitor, as a single agent and in combination with sorafenib. In vitro, we found that carfilzomib has moderate anticancer activity toward liver cancer cells, but strongly enhances the ability of sorafenib to suppress HCC cell growth, proliferation, migration, invasion, and survival. Remarkably, the drug combination exhibits even more potent antitumor activity when tested in animal tumor models. Mechanistically, the combined treatment activates caspase-dependent and endoplasmic reticulum stress/CHOP-mediated apoptotic pathways, and suppresses epithelial-mesenchymal transition. In conclusion, our results demonstrate that the combination of carfilzomib and sorafenib has synergistic antitumor activities against HCC, providing a potential therapeutic strategy to improve the mortality and morbidity of HCC patients.