Inhibition of vascular endothelial growth factor induced mitogenesis of human endothelial cells by a chimeric anti-kinase insert domain-containing receptor antibody

The kinase insert domain-containing receptor (KDR) is the human vascular endothelial growth factor (VEGF) receptor responsible for the mitogenic and angiogenic effects of VEGF. There is much experimental evidence to suggest that the VEGF/KDR pathway plays an important role in tumor angiogenesis, a process essential for tumor growth and metastasis. Here we produced a chimeric anti-KDR antibody (IgG1), c-p1C11, from a single chain (scFv) antibody isolated from a phage display library. C-p1C11 binds specifically to the extracellular domain of soluble as well as cell-surface expressed KDR. It effectively blocks VEGF–KDR interaction and inhibits VEGF-stimulated activation of KDR and MAP kinases p44/p42 of human endothelial cells. Furthermore, c-p1C11 efficiently neutralizes VEGF-induced mitogenesis of human endothelial cells. Our results suggest that antibodies against KDR have potential clinical applications in the treatment of cancer and other diseases where pathological angiogenesis is involved.