CB1 inactivation inhibits endothelial cell proliferation. (A) HUVECs were transfected with either control siRNA or CB1-siRNA for 24 and 48 hours and the lysates were analyzed by immunoblot for CB1 and CB2 expression. (B) HUVECs transfected with either control-siRNA or CB1-siRNA for 24 hours were photographed. Magnification, ×10. (C) BrdU incorporation levels of bFGF-stimulated HUVECs expressed as mean ± SD (relative percentage vs control) of 3 independent experiments in triplicates. (D-F) HUVECs were pretreated or not with CB1 antagonist (30 minutes; D) or CB2 antagonist (30 minutes; F), then stimulated (black bars) or not (white bars) with bFGF (10 ng/mL, 24 hours; D, F) or VEGF (10 ng/mL, 24 hours; E). (G) Lysates were analyzed for CB1 and FGFR expression. Vertical lines have been inserted to indicate a repositioned gel lane. (A,G) Histograms report the quantification of the intensity of the bands calibrated to the intensity of tubulin bands (mean ± SD of 3 independent experiments; ANOVA vs control, *P < .05, **P < .01, ***P < .001).