PPI-2458 reduces VEGF and FGF-2 mediated angiogenesis. Angiogenesis in response to either (a,b,d) 2 ng/ml vascular endothelial growth factor (VEGF) or (c) 50 ng/ml fibroblast growth factor (FGF)-2 was assessed after 11 days. Fumagillin (10 nmol/l) and PPI-2458 (1 nmol/l or 10 nmol/l), or 0.001% dimethyl sulfoxide as a vehicle control were added where indicated. CD31 expression was measured using alkaline phosphatase-mediated conversion of (panel a) p-nitrophenol phosphate followed by colorimetric assay (panels b and c) BCIP/NBT (5-bromo-4-chloro-3-indolyl phosphate/nitro blue tetrazolium) followed by image analysis. Data are expressed as means ± standatd deviation, representative of three experiments, and were analysed by one-way analysis of variance versus response in the absence of inhibitor: **P < 0.01. Included in panel d are representative images showing morphology of the formed tubes stained for CD31 at day 11 (objective magnification 40×).