Figure 5
ERK and c-Src modulate thrombin-induced STAT3 activation in NP cells. (A) NP cells were treated with thrombin for the indicated periods (5, 10, 30, 60, or 120 min), cell lysates were separated by SDS-PAGE and immunoblotted with anti-phosphorylated-ERK, anti-phosphorylated-FAK or anti-phosphorylated-Src. (B) NP cells were treated with thrombin for indicated periods (10, 30, 60 or 120 min), cell lysates were separated by SDS-PAGE and immunoblotted with phosphorylated-STAT3. (C) NP cells were treated with U0126 (1 μM), PF573228 (1 μM), or PP2 (0.3 or 1 μM) for 30 min followed by treatment with thrombin for a further 60 min, and the levels of phosphorylated-STAT3 were determined by western blotting. Similar results were obtained from four independent experiments. (D) NP cells were treated with PF573228 (0.3 or 1 μM), PP2 (0.3 or 1 μM), or U0126 (1 μM) for 30 min followed by treatment with thrombin (10 U/mL) for 24 h (left-hand panel) and the levels of CXCL8 in the culture supernatant were measured by ELISA. NP cells were transfected with siRNA against FAK or non-targeting control for 24 h and were either left unstimulated or were stimulated with thrombin for 24 h before measurement of the CXCL8 levels in the culture supernatant (right-hand panel). Each bar represents the mean ± S.E.M. from at least three independent experiments performed in duplicate. *p < 0.05 compared with the control group. # p < 0.05 compared with the thrombin-treated group.
