Valproic acid overcomes transforming growth factor-β-mediated sorafenib resistance in hepatocellular carcinoma.

Valproic acid overcomes transforming growth factor-β-mediated sorafenib resistance in hepatocellular carcinoma. Int J Clin Exp Pathol. 2014;7(4):1299-313 Authors: Matsuda Y, Wakai T, Kubota M, Osawa M, Hirose Y, Sakata J, Kobayashi T, Fujimaki S, Takamura M, Yamagiwa S, Aoyagi Y Abstract Sorafenib is a multi-kinase inhibitor approved for hepatocellular carcinoma, but rarely causes tumor regression in patients with chronic liver diseases. To investigate whether growth factor-mediated signaling is involved in sorafenib resistance, HepG2 and PLC/PRF/5 hepatoma cells were exposed to epidermal growth factor (EGF), hepatocyte growth factor (HGF) or transforming growth factor-β (TGF-β) prior to treatment with sorafenib. Furthermore, to identify an effective combination treatment with sorafenib, growth factor-sensitized cells were treated with sorafenib alone or in combination with celecoxib, lovastatin or valproic acid (VPA). Trypan blue staining and Annexin V assays showed that the cytotoxic effect of sorafenib was inhibited by 15-54% in cells sensitized to TGF-β (P<0.05). Western blotting analysis showed that TGF-β significantly activated extracellular signal-regulated kinase (ERK)-mediated AKT signaling, and sorafenib failed to suppress both ERK and AKT in TGF-β-sensitized cells. The decreased anti-tumor effect of sorafenib was rescued by chemical inhibition of ERK and AKT. When TGF-β-sensitized cells were treated with sorafeni...
Source: International Journal of Clinical and Experimental Pathology - Category: Pathology Authors: Tags: Int J Clin Exp Pathol Source Type: research