Fig. 6

STAT3 positively regulated ID1 expression at the transcriptional level. A Total cell lysates were prepared from HepG2 or SK-HEP-1 cells subjected to STAT3 or NC siRNAs transfection and used for immunoblotting. B Total cell lysates were prepared from HepG2 or SK-HEP-1 cells subjected to 24 h of JSI-124 (10 µM) treatment and used for immunoblotting. C Total cell lysates were prepared from HepG2 or SK-HEP-1 cells subjected to constitutively activated STAT3 (STAT3C) transfection and used for immunoblotting. D Total RNAs were isolated from both cell lines with or without JSI-124 (10 µM) treatment for 24 h and utilized for quantitative real-time PCR. E Sketch map showing the putative STAT3-binding sequences in the ID1 gene promoter. F Both cell lines, subjected to 24 h treatment with or without 8 µM usenamine A, were used for chromatin immunoprecipitation assay using the anti-STAT3 antibody. The normal rabbit IgG antibody served as the negative control. PCR amplification was conducted with primers around the putative STAT3-binding sites. ^*P < 0.05, ^**P < 0.01, ^***P < 0.001, ^{^^}P < 0.01, and ^{^^^}P < 0.001. The data are representative of three independent experiments, and each was performed at least in triplicate