Vascular endothelial growth factor receptor-2-mediated mitogenesis is negatively regulated by vascular endothelial growth factor receptor-1 in tumor epithelial cells.
Vascular endothelial growth factor (VEGF) receptors are present on nonendothelial cells suggesting that VEGF may mediate nonendothelial effects during organogenesis and tumorigenesis. Here we show that VEGF receptor-1 (VEGFR-1) negatively regulates VEGFR-2-mediated proliferation via nitric oxide (NO) in an epithelial cancer cell line ECV304. Cell proliferation was assessed by [(3)H]thymidine incorporation, fluorescent-activated cell-sorting analysis, and cell number using a Coulter Counter. Total NO generated by the action of nitric oxide synthase was measured by Seivers NOA 280 Nitric Oxide Chemiluminescence Analyser. VEGF (1 ng/ml) stimulated DNA synthesis and increased ECV304 cell number in a manner that was inhibited by a neutralizing anti-VEGFR-2 antibody. In contrast, VEGF (50 ng/ml) stimulated NO release in a manner that was inhibited by functionally neutralizing anti-VEGFR-1 antibody. Blockage of the VEGFR-1 receptor signal with anti-VEGFR-1 stimulated DNA synthesis and increased cell number. Cell-cycle analysis showed that inhibition of VEGFR-1 increased the transition from G(1) to S phase whereas inhibition of VEGFR-2 blocked the VEGF-mediated transition from G(1) to S phase. Finally, the addition of NO donors suppressed both VEGF-mediated proliferation and the increase in growth after blockade of VEGFR-1. Conversely, inhibition of VEGF mediated NO release by nitric oxide synthase inhibitor, L-monomethyl-L-arginine, restored the mitogenic effect of VEGF. These findings identify a dose-dependent reciprocal regulatory mechanism for VEGF via its two receptors. It shows that VEGFR-1 induces cell cytostasis via NO and as such is a suitable target for molecular strategies suppressing tumorigenesis.
Dunk
C
C
Department of Reproductive and Vascular Biology, Division of Reproductive and Child Health, The Medical School, University of Birmingham, Edgbaston, Birmingham, United Kingdom.
Ahmed
A
A
D000911:Antibodies, Monoclonal / Q000494:pharmacology; D002453:Cell Cycle / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D004247:DNA / Q000096:biosynthesis / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D016228:Endothelial Growth Factors / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D008222:Lymphokines / Q000494:pharmacology; D008934:Mitogens / Q000502:physiology*; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D009599:Nitroprusside / Q000494:pharmacology; D010396:Penicillamine / Q000031:analogs & derivatives* / Q000494:pharmacology; D011518:Proto-Oncogene Proteins / Q000276:immunology / Q000502:physiology*; D020794:Receptor Protein-Tyrosine Kinases / Q000276:immunology / Q000502:physiology*; D017978:Receptors, Growth Factor / Q000276:immunology / Q000502:physiology*; D040262:Receptors, Vascular Endothelial Growth Factor; D014407:Tumor Cells, Cultured; D042461:Vascular Endothelial Growth Factor A; D040281:Vascular Endothelial Growth Factor Receptor-1; D042442:Vascular Endothelial Growth Factors; D019323:omega-N-Methylarginine / Q000494:pharmacology
D000911:Antibodies, Monoclonal; D016228:Endothelial Growth Factors; D004791:Enzyme Inhibitors; D008222:Lymphokines; D008934:Mitogens; D011518:Proto-Oncogene Proteins; D017978:Receptors, Growth Factor; C110881:S-nitro-N-acetylpenicillamine; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D009599:Nitroprusside; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D004247:DNA; D019001:Nitric Oxide Synthase; D020794:Receptor Protein-Tyrosine Kinases; D040262:Receptors, Vascular Endothelial Growth Factor; D040281:Vascular Endothelial Growth Factor Receptor-1; D010396:Penicillamine