Abstract
Vascular endothelial cell growth factor (VEGF) binds to and promotes the activation of one of its receptors, KDR. Once activated, KDR induces the tyrosine phosphorylation of cytoplasmic signaling proteins that are important to endothelial cell proliferation. In human umbilical vein endothelial cells (HUVECs), tumor necrosis factor (TNF) inhibits the phosphorylation and activation of KDR. The ability of TNF to diminish VEGF-stimulated KDR activity was impaired by sodium orthovanadate, suggesting that the inhibitory activity of TNF was mediated by a protein-tyrosine phosphatase. KDR-initiated responses specifically associated with endothelial cell proliferation, mitogen-activated protein kinase activation and DNA synthesis, were also inhibited by TNF, and this was reversed by sodium orthovanadate. Stimulation of HUVECs with TNF induced association of the SHP-1 protein-tyrosine phosphatase with KDR, identifying this phosphatase as a candidate negative regulator of VEGF signal transduction. Heterologous receptor inactivation mediated by a protein-tyrosine phosphatase provides insight into how TNF may inhibit endothelial cell proliferative responses and modulate angiogenesis in pathological settings.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Cell Division / drug effects
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Cells, Cultured
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DNA / biosynthesis
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Endothelial Growth Factors / antagonists & inhibitors*
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Endothelium, Vascular / cytology
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Endothelium, Vascular / drug effects*
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Humans
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Intracellular Signaling Peptides and Proteins
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Lymphokines / antagonists & inhibitors*
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Phosphorylation
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Protein Tyrosine Phosphatase, Non-Receptor Type 11
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Protein Tyrosine Phosphatase, Non-Receptor Type 6
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Protein Tyrosine Phosphatases / physiology*
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Receptor Protein-Tyrosine Kinases / analysis
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Receptor Protein-Tyrosine Kinases / antagonists & inhibitors*
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Receptor Protein-Tyrosine Kinases / drug effects
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Receptors, Growth Factor / analysis
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Receptors, Growth Factor / antagonists & inhibitors*
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Receptors, Growth Factor / drug effects
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Receptors, Vascular Endothelial Growth Factor
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Signal Transduction / drug effects
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Tumor Necrosis Factor-alpha / pharmacology*
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Tyrosine / metabolism
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Vascular Endothelial Growth Factor A
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Vascular Endothelial Growth Factors
Substances
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Endothelial Growth Factors
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Intracellular Signaling Peptides and Proteins
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Lymphokines
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Receptors, Growth Factor
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Tumor Necrosis Factor-alpha
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Vascular Endothelial Growth Factor A
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Vascular Endothelial Growth Factors
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Tyrosine
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DNA
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Receptor Protein-Tyrosine Kinases
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Receptors, Vascular Endothelial Growth Factor
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PTPN11 protein, human
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PTPN6 protein, human
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Protein Tyrosine Phosphatase, Non-Receptor Type 11
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Protein Tyrosine Phosphatase, Non-Receptor Type 6
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Protein Tyrosine Phosphatases