Figure 7

Effects of STAT3 siRNA treatment on IL-22-induced STAT3 phosphorylation (a and b), REG Iα promoter activity (c and d), and REG Iα protein expression (e and f) in colon cancer cells. SW403 (a and e: 1 × 10⁶) and LoVo cells (b and f: 1 × 10⁶) were transfected with STAT3 siRNA (or non-silencing siRNA as a control) for 48 h. After transfection, the cells were stimulated with IL-22 (10 ng/ml) for 15 min to evaluate STAT3 phosphorylation (a and b), and for 24 h to evaluate REG Iα protein expression (e and f). Extracted protein was analyzed using western blotting. SW403 (c: 8 × 10⁴) and LoVo cells (d: 8 × 10⁴) were co-transfected with hREG Iα (−1195/+78)-Luc construct, Renilla luciferase plasmid pRL-TK, and STAT3 siRNA (or non-silencing siRNA as a control) for 48 h. After transfection, cells were stimulated with IL-22 (10 ng/ml) for 24 h and luciferase activity was measured. The results are expressed as the proportion of the activity of the untreated cell group and represented as the mean±s.e.m. of four samples. ^*P<0.01 vs the untreated cell group, ^#P<0.01 vs IL-22-treated cell group.