miR-155 post-transcriptionally inhibited SOCS1 and activated JAK/STAT signaling pathway in human hepatoma cells. (A) Analysis of SOCS1 mRNA levels by RT-PCR. Total RNA was extracted from HepG2 and HepG2-miR155 cells, and HepG2 cells transfected with 50 nM miR-155 mimics or control RNA. (B) SOCS1, (C) p-STAT1 and p-STAT3 protein levels in cells above were tested by western blot analysis. (D, E) Relative density analysis of the IFN-induced gene protein levels. (F) Western blot analysis of ISG15, SOCS1, p-STAT1 and p-STAT3 protein levels in H7402 cells were performed 48h after transfection. (G) Relative density analysis of the IFN-induced gene protein levels in H7402. One representative of three independent experiments was shown.