Figure 8

Effects of MEK inhibitor or PI3K–Akt inhibitor on IL-22-induced ERK phosphorylation, Akt 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 pretreated with 20 μM PD98059 or 100 nM wortmannin for 45 min and then stimulated with IL-22 (10 ng/ml) for 15 min to detect ERK and Akt phosphorylation (a and b), and for 24 h to detect REG Iα protein expression (e and f). SW403 (c: 8 × 10⁴) and LoVo cells (d: 8 × 10⁴) were co-transfected with hREG Iα (−1195/+78)-Luc construct and Renilla luciferase plasmid pRL-TK for 48 h. After transfection, cells were treated with 20 μM PD98059 or 100 nM wortmannin for 45 min, 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.