Sema3A interferes with VEGF- but not bFGF-induced angiogenesis. (A) Inhibition of VEGF- but not bFGF-mediated angiogenesis by Sema3A was determined by treating CAMs with PBS, VEGF (40 μg/mL), and bFGF (40 μg/mL) with or without Sema3A (50 μg/mL) for 3 days (n = 15, **P < .01). Error bars represent SEM. (B,C) Increasing concentrations of Sema3A (ng/mL) selectively suppresses FAK and Src activation in VEGF- but not bFGF-stimulated (5 minutes) cells. Phosphorylation of FAK, Src, and ERK was determined through immunoblotting. (D) HUVECs were treated with 250 ng/mL Sema3A prior to stimulation with VEGF throughout various time points. These experiments were repeated multiple times with similar results.