Selective inhibition of vascular endothelial growth factor receptor-2 (VEGFR-2) identifies a central role for VEGFR-2 in human aortic endothelial cell responses to VEGF.
Vascular endothelial growth factor receptors (VEGFR) are considered essential for angiogenesis. The VEGFR-family proteins consist of VEGFR-1/Flt-1, VEGFR-2/KDR/Flk-1, and VEGFR-3/Flt-4. Among these, VEGFR-2 is thought to be principally responsible for angiogenesis. However, the precise role of VEGFRs1-3 in endothelial cell biology and angiogenesis remains unclear due in part to the lack of VEGFR-specific inhibitors. We used the newly described, highly selective anilinoquinazoline inhibitor of VEGFR-2 tyrosine kinase, ZM323881 (5-[[7-(benzyloxy) quinazolin-4-yl]amino]-4-fluoro-2-methylphenol), to explore the role of VEGFR-2 in endothelial cell function. Consistent with its reported effects on VEGFR-2 [IC(50) < 2 nM], ZM323881 inhibited activation of VEGFR-2, but not of VEGFR-1, epidermal growth factor receptor (EGFR), platelet-derived growth factor receptor (PDGFR), or hepatocyte growth factor (HGF) receptor. We studied the effects of VEGF on human aortic endothelial cells (HAECs), which express VEGFR-1 and VEGFR-2, but not VEGFR-3, in the absence or presence of ZM323881. Inhibition of VEGFR-2 blocked activation of extracellular regulated-kinase, p38, Akt, and endothelial nitric oxide synthetase (eNOS) by VEGF, but did not inhibit p38 activation by the VEGFR-1-specific ligand, placental growth factor (PIGF). Inhibition of VEGFR-2 also perturbed VEGF-induced membrane extension, cell migration, and tube formation by HAECs. Vascular endothelial growth factor receptor-2 inhibition also reversed VEGF-stimulated phosphorylation of CrkII and its Src homology 2 (SH2)-binding protein p130Cas, which are known to play a pivotal role in regulating endothelial cell migration. Inhibition of VEGFR-2 thus blocked all VEGF-induced endothelial cellular responses tested, supporting that the catalytic activity of VEGFR-2 is critical for VEGF signaling and/or that VEGFR-2 may function in a heterodimer with VEGFR-1 in human vascular endothelial cells.
Endo
Akira
A
Department of Structural Analysis, National Cardiovascular Center Research Institute, Cardiovascular Center Research Institute, Suita, Osaka, Japan.
Fukuhara
Shigetomo
S
Masuda
Michitaka
M
Ohmori
Toyonori
T
Mochizuki
Naoki
N
D000818:Animals; D001011:Aorta / Q000033:anatomy & histology*; D002462:Cell Membrane / Q000378:metabolism; D002465:Cell Movement / Q000502:physiology; D050719:Crk-Associated Substrate Protein; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology* / Q000378:metabolism; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D051379:Mice; D041681:NIH 3T3 Cells; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D017346:Protein Serine-Threonine Kinases; D011506:Proteins / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D011799:Quinazolines / Q000494:pharmacology; D020794:Receptor Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D017479:Receptors, Platelet-Derived Growth Factor / Q000378:metabolism; D050717:Retinoblastoma-Like Protein p130; D015398:Signal Transduction / Q000502:physiology; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism*
C493841:BCAR1 protein, human; C493842:Bcar1 protein, mouse; D050719:Crk-Associated Substrate Protein; D004791:Enzyme Inhibitors; D011506:Proteins; D011518:Proto-Oncogene Proteins; D011799:Quinazolines; D050717:Retinoblastoma-Like Protein p130; D042461:Vascular Endothelial Growth Factor A; C478783:ZM323881; C496314:NOS3 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496315:Nos3 protein, mouse; D020794:Receptor Protein-Tyrosine Kinases; D017479:Receptors, Platelet-Derived Growth Factor; D040301:Vascular Endothelial Growth Factor Receptor-2; C494918:AKT1 protein, human; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt