Hepatitis B virus X (HBx)
protein has been known to play an important role in development of
hepatocellular carcinoma (HCC). The aim of this study is to find out whether HBx
protein expression affects antiproliferative effect of an
epidermal growth factor receptor-
tyrosine kinase (EGFR-TK) inhibitor and a
MEK inhibitor in HepG2 and Huh-7 cell lines. We established HepG2 and Huh-7 cells transfected stably with HBx gene. HBx
protein expression increased pERK and pAkt expression as well as β-
catenin activity in both cells.
Gefitinib (EGFR-TK inhibitor) inhibited pERK and pAkt expression and β-
catenin activity in both cells.
Selumetinib (
MEK inhibitor) reduced pERK level and β-
catenin activity but pAkt expression was rather elevated by
selumetinib in these cells. Reduction of pERK levels was much stronger with
selumetinib than
gefitinib in both cells. The antiproliferative efficacy of
selumetinib was more potent than that of
gefitinib. However, the antiproliferative effect of
gefitinib, as well as
selumetinib, was not different between cell lines with or without HBx expression. Signal pathway activation by HBx might not be strong enough to attenuate the antiproliferative effect of EGFR-TK inhibitor. Future experiments are needed to understand the role of HBx
protein expression in HCC treatment using molecular targeting agent.