JK-31 inhibits growth factor-stimulated receptor activation and downstream signal transduction.

<p>(A) HUVECs were pre-treated with JK-31 (0, 0.1, 1, 10 or 50 µM) for 30 min followed by 7.5 min stimulation with VEGF-A (25 ng/ml) in the presence of JK-31. Total cell lysates were prepared and processed for immunoblotting. Levels of phosphorylated VEGFR2, PLCγ1, Akt and ERK were analysed using phospho-specific antibodies. Membranes were stripped and re-probed for total protein levels and a loading control (α-tubulin). (B) Densitometric quantification of phosphorylated VEGFR2-pY1175 levels in response to VEGF-A and JK-31 treatment. Error bars represent ± SEM (n = 4; ***<i>p</i><0.001). (C-D) JK-31 inhibits FGF-stimulated intracellular signaling in endothelial cells. HUVECs were pre-treated with JK-31 (0, 0.1, 1, 10 or 50 µM) for 30 min followed by 10 min stimulation with either (C) bFGF (50 ng/ml) or (D) aFGF (50 ng/ml) in the presence of JK-31. Cells were lysed and processed for immunoblotting. Representative immunoblots of three independent experiments are shown.