Interferon alpha regulates MAPK and STAT1 pathways in human hepatoma cells

Background: Signaling events triggered by interferon (IFN) account for the molecular mechanisms of antiviral effect. JAK STAT pathway plays a critical role in IFN signaling, and other pathways are also implicated in IFN mediated antiviral effect. Changes in mitogen-activated protein kinase (MAPK) and STAT1 pathways were evaluated in human hepatoma cells Huh7 and HepG2 upon IFN alpha treatment. Results: Phosphorylation of ERK was significantly and specifically up-regulated, whereas enhanced phosphorylation of upstream kinase MEK was unobservable upon IFN alpha treatment. A mild increase in p38 MAPK, SAPK/JNK and downstream target ATF-2 phosphorylation was detectable after exposure to IFN alpha, indicating differential up-regulation of the MAPK signaling cascades. Moreover, STAT1 phosphorylation was strongly enhanced by IFN alpha. Conclusion: IFN alpha up-regulates MAPK and STAT1 pathways in human hepatoma cells, and may provide useful information for understanding the IFN signaling.