Vascular Endothelial Growth Factor 165 (VEGF sub(165)) Activities Are Inhibited by Carboxymethyl Benzylamide Dextran That Competes for Heparin Binding to VEGF sub(165) and VEGF sub(165) super(.)KDR Complexes

• Published in: The Journal of biological chemistry 2001-10, Vol.276 (43), p.39748-39754
• Main Authors: Hamma-Kourbali, Y, Vassy, R, Starzec, A, Le Meuth-Metzinger, V, Oudar, O, Bagheri-Yarmand, R, Perret, G, Crepin, M
• Format: Article
• Language: English
• Subjects: carboxymethyl benzylamide dextran; KDR protein; vascular endothelial growth factor
• ISSN: 0021-9258

We have previously shown that carboxymethyl dextran benzylamide (CMDB7), a heparin-like molecule, inhibits the growth of tumors xenografted in nude mice, angiogenesis, and metastasis by altering the binding of angiogenic growth factors, including platelet-derived growth factor, transforming growth factor beta , and fibroblast growth factor 2, to their specific receptors. In this study, we explore the effect of CMDB7 on the most specific angiogenic growth factor, vascular endothelial growth factor 165 (VEGF sub(165)). We demonstrate here that CMDB7 inhibits the mitogenic effect of VEGF sub(165) on human umbilical vein endothelial cells (HUV-ECs) by preventing the VEGF sub(165)-induced VEGF receptor-2 (KDR) autophosphorylation and consequently a specific intracellular signaling. In competition experiments, the binding of super(125)I-VEGF sub(165) to HUV-ECs is inhibited by CMDB7 with an IC sub(50) of 2 mu M. Accordingly, CMDB7 inhibits the cross-linking of super(125)I-VEGF sub(165) to the surface of HUV-ECs, causing the disappearance of both labeled complexes, 170-180 and 240-250 kDa. We show that CMDB7 increases the electrophoretic mobility of VEGF sub(165), thus evidencing formation of a stable complex with this factor. Moreover, CMDB7 reduces the super(125)I-VEGF sub(165) binding to coated heparin-albumin and prevents a heparin-induced increase in iodinated VEGF sub(165) binding to soluble super(125)I-KDR-Fc chimera. Concerning KDR, CMDB7 has no effect on super(125)I-KDR-Fc electrophoretic migration and does not affect labeled KDR-Fc binding to coated heparin-albumin. In the presence of VEGF sub(165), super( 125)I-KDR-Fc binding to heparin is enhanced, and under these conditions, CMDB7 interferes with KDR binding. These data indicate that CMDB7 effectively inhibits the VEGF sub(165) activities by interfering with heparin binding to VEGF sub(165) and VEGF sub(165) super(.)KDR complexes but not by direct interactions with KDR.