MEAN inhibits hepatitis C virus replication by interfering with a polypyrimidine tract-binding protein.

MEAN (6-methoxyethylamino-numonafide) is a small molecule compound, and here, we report that it effectively inhibits hepatitis C virus (HCV) infection in an HCV cell culture system using a JC1-Luc chimeric virus, with a 50% effective concentration (EC50) of 2.36 ± 0.29 μM. Drug combination usage analyses demonstrated that MEAN was synergistic with interferon α, ITX5061 and ribavirin. In addition, MEAN effectively inhibits N415D mutant virus and G451R mutant viral infections. Mechanistic studies show that the treatment of HCV-infected hepatocytes with MEAN inhibits HCV replication but not translation. Furthermore, treatment with MEAN significantly reduces polypyrimidine tract-binding protein (PTB) levels and blocks the cytoplasmic redistribution of PTB upon infection. In the host cytoplasm, PTB is directly associated with HCV replication, and the inhibition of HCV replication by MEAN can result in the sequestration of PTB in treated nuclei. Taken together, these results indicate that MEAN is a potential therapeutic candidate for HCV infection, and the targeting of the nucleo-cytoplasmic translocation of the host PTB protein could be a novel strategy to interrupt HCV replication.