SURAMIN INHIBITS BFGF-INDUCED ENDOTHELIAL-CELL PROLIFERATION AND ANGIOGENESIS IN THE CHICK CHORIOALLANTOIC MEMBRANE

The effects of suramin, an inhibitor of growth factor mitogenic activi ty, were evaluated on basic fibroblast growth factor (bFGF)-induced pr oliferation of bovine aortic endothelial cells and on angiogenesis in the chorioallantoic membrane (CAM) of chick embryos. The role of bFGF gene expression in endothelial cell growth was also investigated by us ing an antisense oligodeoxynucleotide to bFGF. The 4-fold increase in [H-3]-thymidine uptake in endothelial cells in vitro upon stimulation with 10 ng ml-1 of bFGF was inhibited by suramin 300 mug ml-1. bFGF an tisense oligomer (10 mum) reduced [H-3]-thymidine incorporation in exp onentially growing cells by 76%; this effect was reversed by bFGF 10 n g ml-1. In the CAM of chick embryos suramin 50 mug was a more potent i nhibitor of angiogenesis than the combination of heparin 60 mug/hydroc ortisone 50 mug; the mean value of the area with reduced vascularity w as significantly larger in suramin-treated CAMs (2.4 cm2) than in hepa rin/hydrocortisone (0.6 cm2), while the reduction of vascular density was similar (-35 and -29% compared to controls, respectively), In conc lusion, the effects of treatments with bFGF and bFGF antisense oligome r demonstrate that bFGF plays a relevant role in endothelial cell prol iferation and may be the target of suramin since the drug is able to s uppress basal and bFGF-induced endothelial cell growth; in addition to this, suramin is a more potent angiogenesis inhibitor in the CAM than the combination of heparin/hydrocortisone.