Figure 3. Effects of cyclopamine on in vitro angiogenesis in HUVECs on fibroblast feeder layer. Tube formation in the presence of vascular endothelial growth factor (VEGF) was not affected by the addition of cyclopamine at the concentrations of 2.5 and 10.0 ng/ml as revealed by the evaluation of the total length of CD31-positive tissue (A) and the numbers of its branching (B).