Effect of hepatitis C virus core protein and NS4B on the proliferation of HepG2 cells

Abstract

Objective To investigate the effect of hepatitis C virus (HCV) core protein and nonstructural protein 4B(NS4B) on the proliferation of HepG2 cells and its possible mechanism.Methods The two recombinant plasmid pcDNA3.1 (-)Core and pcDNA3.1 (-) NS4B were transiently transfected respectively and co-transfected into HepG2 cells by lipofectamine, simultaneously HepG2 cells transfected with pcDNA3.1 (-) and untransfected HepG2 cells were used as control.The expression of mRNA and protein of HCV Core,NS4B,Wnt1,β-catenin,c-myc and CyclinDl in the cells of each group were detected by RT-PCR and Western blot respectively.Cell proliferation changes were measured by MTT assay and plate colony formation assay.The cell cycle distribution was tested by flow cytometry.Results ①HCV Core or/and NS4B mRNA and protein were expressed successfully in the HepG2 cells transfected with pcDNA3.1 (-)Core,pcDNA3.1 (-)NS4B alone or in combination.② The relative expression levels of mRNA and protein of Wnt1,β-catenin,c-myc and CyclinD1 were higher in the cells transfected with pcDNA3.1 (-) Core,pcDNA3.1 (-) NS4B alone or in combination than those in the cells transfected with pcDNA3.1 (-) and untransfected HepG2 cells(P ＜0.01).③Compared with the HepG2 cells transfected with pcDNA3.1 (-)and untransfected,cell viability,cloning efficiency and the percentage of cells at S and G2/M phases were significantly increased in the cells transfected with pcDNA3.1 (-) Core,pcDNA3.1 (-) NS4B alone or in combination (P ＜ 0.01).Conclusion HCV core protein and NS4B can accelerate cell cycle progression and promote cell proliferation of HepG2 cells probably through enhancement of Wntl,β-catenin,c-myc and CyclinD1 expression. Key words: Hepatitis viruses; Viral core proteins; Viral nonstructural proteins; Cell division