AN ANTAGONISTIC VASCULAR ENDOTHELIAL GROWTH-FACTOR (VEGF) VARIANT INHIBITS VEGF-STIMULATED RECEPTOR AUTOPHOSPHORYLATION AND PROLIFERATION OF HUMAN ENDOTHELIAL-CELLS

Vascular endothelial growth factor (VEGF) is a potent mitogen with a u nique specificity for endothelial cells and a key mediator of aberrant endothelial cell proliferation and vascular permeability in a variety of human pathological situations, such as tumor angiogenesis, diabeti c retinopathy, rheumatoid arthritis, or psoriasis. VEGF is a symmetric homodimeric molecule with two receptor binding interfaces lying on ea ch pole of the molecule. Herein we report on the construction and reco mbinant expression of an asymmetric heterodimeric VEGF variant with an intact receptor binding interface at one pole and a mutant receptor b inding interface at the second pole of the dimer. This VEGF variant bi nds to VEGF receptors but fails to induce receptor activation, In comp etition experiments, the heterodimeric VEGF variant antagonizes VEGF-s timulated receptor autophosphorylation and proliferation of endothelia l cells. A 15-fold excess of the heterodimer was sufficient to inhibit VEGF-stimulated endothelial cell proliferation by 50%, and a 100-fold excess resulted in an almost complete inhibition. By using a rational approach that is based on the structure of VEGF, we have shown the fe asibility to construct a VEGF variant that acts as an VEGF antagonist.