EGFR and EphA2 are host factors for hepatitis C virus entry and possible targets for antiviral therapy

Treatment options for hepatitis C virus (HCV) infection have limited efficacy and high toxicity, resulting in poor adherence and, thus, viral resistance. Identifying previously unrecognized pathways involved in HCV infection may aid the development of new therapeutics. Using an RNAi screen, Lupberger et al. have identified cellular kinases involved in HCV infection of liver cells and have tested the ability of approved inhibitors to block viral entry both in vitro and in vivo. Hepatitis C virus (HCV) is a major cause of liver disease, but therapeutic options are limited and there are no prevention strategies. Viral entry is the first step of infection and requires the cooperative interaction of several host cell factors. Using a functional RNAi kinase screen, we identified epidermal growth factor receptor and ephrin receptor A2 as host cofactors for HCV entry. Blocking receptor kinase activity by approved inhibitors broadly impaired infection by all major HCV genotypes and viral escape variants in cell culture and in a human liver chimeric mouse model in vivo. The identified receptor tyrosine kinases (RTKs) mediate HCV entry by regulating CD81–claudin-1 co-receptor associations and viral glycoprotein–dependent membrane fusion. These results identify RTKs as previously unknown HCV entry cofactors and show that tyrosine kinase inhibitors have substantial antiviral activity. Inhibition of RTK function may constitute a new approach for prevention and treatment of HCV infection.