BK-mediated ERK1/2-STAT3/FGF-2 signaling activation requires FGFR-1. (A) ERK1/2 and (B) STAT3 phosphorylation were evaluated using western blot analysis in HUVEC treated with SU5402 (1 μM, 30 min), then stimulated with BK (1 μM) for 15 min. Results were normalized to ERK1/2 and STAT3, respectively. (C) FGFR-1 expression evaluated using western blot analysis in HUVEC transfected with two different shRNA for FGFR-1 knock-down (Sh#1 and Sh#2). EV = empty vector. (D,E) Western blot analysis for ERK1/2 and STAT3 phosphorylation in HUVEC transfected with Sh#1 and Sh#2 and stimulated with BK (1 μM) for 15 min. (F) FGF-2 expression was evaluated in HUVEC treated with STAT3 inhibitor (10 μM, 30 min) and then stimulated with BK (1 μM) for 24 h. Actin was used as a loading control. The results presented are representative of three independent experiments (n = 3) with similar results. Quantification was expressed as an arbitrary density unit (ADU). ** p < 0.01; *** p < 0.001 vs. Ctr; ###
p < 0.001 vs. BK treated cells.