Figure 5: The activation of STAT3 regulated the expression of HCCR.

(A) AGS and MGC-803 cells were treated with various concentrations of IL-6 for 1 h. HCCR expression increased as the IL-6 concentration increased. (B) The NCI-N87 cells were treated with 100 IU/mL IL-6 for 0.25 h, 0.5 h, 1.0 h, 6.0 h, and 12 h. An increase in HCCR expression was rapidly detectable within 0.5 h. The increase in p-STAT3 was detectable within 0.25 h and was lasted for 12 h. (C) IL-6 increased the expression of HCCR, but HCCR expression was blocked by the STAT3 inhibitor S3I-201. (D) Schematic drawing representing the step-by-step deletion of the HCCR-promoter luciferase (Luc)-reporter constructs as well as mutant (mt)- and wild type (WT)-reporter constructs. Relative locations of the putative binding sites are shown. Cells were transfected with different reporters for 24 h and were treated with or without IL-6 and its inhibitor (S31-201). Luciferase reporter activities were detected. The results are shown as the means (±s.d.) of three separate experiments.