Effect of Eap on endothelial-cell proliferation and capillary sprout formation. (A) HUVEC proliferation. HUVECs were incubated without (□) or with (▪) VEGF (10 ng/mL) in the absence (–) or presence of increasing concentrations of Eap as indicated. Proliferation of HUVECs is expressed as a percentage of control, defined as cell proliferation in the absence of any stimulus or competitor. Data are means ± SD (n = 3) of 1 experiment typical of 3 separate experiments performed. (B-C) Capillary sprout formation. (B) HUVECs were incubated for 24 hours in the absence (–; □) or presence (▪) of VEGF (25 ng/mL) with or without increasing concentrations of Eap, as indicated. Capillary-like tube formation is expressed as capillary sprout length in micrometers. (C) HUVECs were incubated for 24 hours in the presence of VEGF (25 ng/mL) with or without (–) Eap, protein A (each 20 μg/mL), cyclic RGD peptide (cRGD; 20 μg/mL), or the mAb against α_vβ₃-integrin, LM609 (20 μg/mL), as indicated. Capillary-like tube formation is expressed relative to control, which is represented as sprout formation in the presence of VEGF and in the absence of any competitor. Data are means ± SD (n = 10) of a representative experiment. Similar results were obtained in 3 independent experiments.