Figure 6

Effects of TPA and STE on the MAPK pathway. (A) HONE-1 cells were treated with TPA (50 ng/mL) for 15, 30, 60, and 120 min and then subjected to Western blotting to analyze the levels of Erk 1/2, JNK, and p38. (B) HONE-1 cells were treated with STE (0, 50, and 100 μg/mL) in the presence or absence of TPA (50 ng/mL) for 6 h and then subjected to Western blotting to analyze the levels of Erk 1/2, JNK and p38. (C) HONE-1 cells were pre-treated with U0126 (10 μM), SP600125 (10 μM) and SB203580 (10 μM) for 30 min and then incubated with TPA (50 ng/mL) for 24 h. The medium was subjected to gelatin zymography as described in the Methods. (D) HONE-1 cells were pre-treated with U0126 (10 or 20 μM) for 30 min and then incubated in the presence or absence of TPA (50 ng/mL) and STE (50 μg/mL) for 24 h. The medium was subjected to gelatin zymography. The values represented the means±SD of at least three independent experiments. #p< 0.05 compared to the vehicle group; *p< 0.05 compared to the TPA treatment group.