BB-24 inhibits VEGF-mediated endothelial cell proliferation. HUVECs were incubated with increasing concentrations of BB-24 for 1 hour before the addition of 1 ng/mL bFGF or 20 ng/mL VEGF. After overnight incubation, BrdU was added for an additional 24 hours before measuring incorporation as described in Materials and Methods. Plates were read at 450 nm and results are expressed as mean percentage of control ± SD, where 100% control represents BrdU incorporation in the absence of inhibitor.