Abstract 1093: Synergistic action of sorafenib and carfilzomib against hepatocellular carcinoma in vitro and in vivo
Authors: Jiang Chao , Xu Rui , Li Xiao-Xing , Wang Hui-Yun , Zheng X.F. Steven 
Published: July 2017

Abstract
Background: Sorafenib, a multikinase inhibitor, is currently the only approved systemic drug for advanced hepatocellular carcinoma (HCC), but has demonstrated limited survival benefits for patients. Carfilzomib (CFZ) is a second-generation proteasome inhibitor approved for the treatment of multiple myeloma. In this study, we aim to investigate the synergistic antitumor effect of the combined treatment of sorafenib and CFZ in hepatocellular carcinoma and the underlying molecular mechanisms.
Methods: Hep3B and Bel-7402 HCC cell lines were treated with sorafenib and/or CFZ at clinically relevant concentrations, after which effects on cell viability and proliferation were analyzed using MTS method; cell migration and invasion were evaluated in transwell assay; cell apoptosis were monitored by flow cytometry. Western blot assay was used to investigate the potential molecular mechanism of the synergistic antitumor effect of the combined treatment. In vivo efficacy was determined in nude mice with Hep3B xenografts.
Results: MTS results showed that CFZ could improve the drug sensitivities of sorafenib in Hep3B and Bel-7402 cells when combined these two drugs together. Moreover, cell proliferation was more significantly suppressed in combinational treatment compared to single agent (p &lt; 0.01) in the two tested cell lines. The colony formation assay showed similar results with the MTS assay. The results from flow cytometry showed that sorafenib or CFZ alone induced about 11% apoptotic cells in Hep3B, when administered in combination the percentage of apoptotic cells significantly increased to about 20.78% (p &lt; 0.01). Similar results were observed in Bel-7402. Results of transwell assay demonstrated that cell migration and invasion ability were inhibited when treated with sorafenib or CFZ alone; and cells treated with the combinational therapy migrated and invaded even less (p &lt; 0.05). The in vivo xenograft tumor model showed that treatment with sorafenib or CFZ inhibited Hep3B tumor growth (p &lt; 0.05); moreover, treatment with the combination more significantly inhibited tumor growth (p &lt; 0.01). Mechanistically, combined treatment of the two drugs suppressed the epithelial-mesenchymal transition process by increasing E-cadherin and decreasing N-cadherin and β-catenin. Furthermore, the drug combination activated the mitochondria-related apoptosis pathway, showing up-regulation of cleaved caspase 3/7/9. Up-regulations of PERK/eIF2α/ATF4/CHOP pathway implicated the involvement of ER stress-mediated apoptotic pathway following the drug combination treatment.
Conclusion: In conclusion, these findings suggest that the combination of sorafenib and CFZ shows synergistic antitumor activities in HCC, potentially providing a novel therapeutic strategy for patients with advanced hepatocellular carcinoma.
Citation Format: Chao Jiang, Rui Xu, Xiao-Xing Li, Hui-Yun Wang, X.F. Steven Zheng. Synergistic action of sorafenib and carfilzomib against hepatocellular carcinoma in vitro and in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1093. doi:10.1158/1538-7445.AM2017-1093