Original Article
Copyright ©2014 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. May 7, 2014; 20(17): 4953-4962
Published online May 7, 2014. doi: 10.3748/wjg.v20.i17.4953
Inhibition of autophagy significantly enhances combination therapy with sorafenib and HDAC inhibitors for human hepatoma cells
Hang Yuan, Ai-Jun Li, Sen-Lin Ma, Long-Jiu Cui, Bin Wu, Lei Yin, Meng-Chao Wu
Hang Yuan, Ai-Jun Li, Sen-Lin Ma, Long-Jiu Cui, Bin Wu, Lei Yin, Meng-Chao Wu, Department of the 2nd Special Treatment, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai 200438, China
Author contributions: Yuan H, Li AJ and Ma SL performed the majority of the experiments; Cui LJ, Wu B and Yin L provided vital reagents and analytical tools and were involved in editing the manuscript; Li AJ and Wu MC coordinated and provided the collection of human materials and provided financial support for this work; Yuan H and Li AJ designed the study and wrote the manuscript.
Supported by Eastern Hepatobiliary Surgery Hospital of the Second Military Medical University
Correspondence to: Ai-Jun Li, MD, Department of the 2nd Special Treatment, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, No. 225, Changhai Road, Shanghai 200438, China. ajli62@gmail.com
Telephone: +86-21-81875531 Fax: +86-21-81875531
Received: August 25, 2013
Revised: December 4, 2013
Accepted: January 2, 2014
Published online: May 7, 2014
Abstract

AIM: To clarify whether histone deacetylase inhibitors histone deacetylase inhibitors (HDACIs) can sensitize hepatocellular carcinoma (HCC) cells to sorafenib treatment.

METHODS: Bax, Bcl-2, ATG5-ATG12, p21, and p27 protein levels in Hep3B, HepG2, and PLC/PRF/5 cells were examined by Western blot. CCK8 and a fluorometric caspase-3 assay were used to examine cellular viability and apoptosis levels. The effect of Beclin-1 on sensitization of HCC cells to sorafenib was examined by transfecting Beclin-1 siRNA into Hep3B, HepG2, and PLC/PRF/5 cells.

RESULTS: Autophagy inhibition enhances the inhibitory effects of vorinostat and sorafenib alone or in combination on HCC cell growth. Vorinostat and sorafenib synergistically induced apoptosis and cell cycle alterations. Western blot data indicated that HDACIs and Beclin-1 knockdown increased the p53 acetylation level. The knockdown of Beclin-1 enhanced the synergistic effect of the combination of vorinostat with sorafenib.

CONCLUSION: HDACIs can sensitize HCC cells to sorafenib treatment by regulating the acetylation level of Beclin-1.

Keywords: Hepatocellular carcinoma, Histone deacetylase inhibitors, Autophagy, Sorafenib, Chemoresistance

Core tip: In this study, we investigated the antiproliferative effect of sorafenib in combination with the histone deacetylase inhibitor vorinostatin in human hepatoma cell lines (Hep3B, HepG2, and PLC/PRF/5). We also examined whether the combination therapy was enhanced by the inhibition of autophagy. Our results showed that the combination of vorinostat with sorafenib synergistically reduced cell proliferation in hepatocellular carcinoma cells by inducing apoptosis and cell cycle arrest. Synergistic changes in cell cycle and cell survival regulators were also observed.