Vascular endothelial growth factor (VEGF) receptor II-derived peptides inhibit VEGF

Vascular endothelial growth factor (VEGF) directly stimulates endothelial cell proliferation and migration via tyrosine kinase receptors of the split kinase domain family. It mediates vascular growth and angiogenesis in the embryo but also in the adult in a variety of physiological and pathological conditions. The potential binding site of VEGF with its receptor was identified using cellulose-bound overlapping peptides of the extracytosolic part of the human vascular endothelial growth factor receptor II (VEGFR II). Thus, a peptide originating from the third globular domain of the VEGFR II comprising residues (247)RTELNVGIDFNWEYP(261) was revealed as contiguous sequence stretch, which bound I-125-VEGF(165). A systematic replacement with L-amino acids within the peptide representing the putative VEGF-binding site on VEGFR II indicates Asp(255) as the hydrophilic key residue for binding. The dimerized peptide (RTELNVGIDFNWEYPAS)(2)K inhibits VEGF(165) binding with an IC50 of 0.5 mu M on extracellular VEGFR II fragments and 30 mu M on human umbilical vein cells. VEGF(165)-stimulated autophosphorylation of VEGFR II as well as proliferation and migration of microvascular endothelial cells was inhibited by the monomeric peptide RTELNVGIDFNWEYPASK at a half-maximal concentration of 3-10, 0.1, and 0.1 mu M, respectively, We conclude that transduction of the VEGF(165) signal can be interrupted with a peptide derived from the third Ig-like domain of VEGFR LI by blockade of VEGF(165) binding to its receptor.