Abstract
Endorepellin, the angiostatic C-terminal domain of the heparan sulfate proteoglycan perlecan, inhibits angiogenesis by simultaneously binding to the α2β1 integrin and the vascular endothelial growth factor (VEGF) receptor 2 (VEGFR2) on endothelial cells. This interaction triggers the down-regulation of both receptors and the concurrent activation of the tyrosine phosphatase SHP-1, which leads to a signaling cascade resulting in angiostasis. Here, we provide evidence that endorepellin is capable of attenuating both the PI3K/PDK1/Akt/mTOR and the PKC/JNK/AP1 pathways. We show that hypoxia-inducible factor 1α (HIF-1α) transcriptional activity induced by VEGFA was inhibited by endorepellin independent of oxygen concentration and that only a combination of both PI3K and calcineurin inhibitors completely blocked the suppressive activity evoked by endorepellin on HIF1A and VEGFA promoter activity. Moreover, endorepellin inhibited the PKC/JNK/AP1 axis induced by the recruitment of phospholipase γ and attenuated the VEGFA-induced activation of NFAT1, a process dependent on calcineurin activity. Finally, endorepellin inhibited VEGFA-evoked nuclear translocation of NFAT1 and promoted NFAT1 stability. Thus, we provide evidence for a novel downstream signaling axis for an angiostatic fragment and for the key components involved in the dual antagonistic activity of endorepellin, highlighting its potential use as a therapeutic agent.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Active Transport, Cell Nucleus / physiology
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Animals
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Cell Nucleus / genetics
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Cell Nucleus / metabolism*
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Cells, Cultured
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Heparan Sulfate Proteoglycans / genetics
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Heparan Sulfate Proteoglycans / metabolism*
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Human Umbilical Vein Endothelial Cells / cytology
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Human Umbilical Vein Endothelial Cells / metabolism*
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Humans
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Hypoxia-Inducible Factor 1, alpha Subunit / genetics
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Hypoxia-Inducible Factor 1, alpha Subunit / metabolism*
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MAP Kinase Kinase 4 / genetics
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MAP Kinase Kinase 4 / metabolism
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MAP Kinase Signaling System / physiology*
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NFATC Transcription Factors / genetics
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NFATC Transcription Factors / metabolism*
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Neovascularization, Physiologic / physiology*
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Peptide Fragments / genetics
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Peptide Fragments / metabolism*
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Phosphatidylinositol 3-Kinases / genetics
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Phosphatidylinositol 3-Kinases / metabolism
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Protein Kinase C / genetics
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Protein Kinase C / metabolism
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Protein Serine-Threonine Kinases / genetics
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Protein Serine-Threonine Kinases / metabolism
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Proto-Oncogene Proteins c-akt / genetics
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Proto-Oncogene Proteins c-akt / metabolism
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Pyruvate Dehydrogenase Acetyl-Transferring Kinase
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Swine
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TOR Serine-Threonine Kinases / genetics
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TOR Serine-Threonine Kinases / metabolism
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Transcription, Genetic / physiology*
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Vascular Endothelial Growth Factor A / genetics
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Vascular Endothelial Growth Factor A / metabolism*
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Vascular Endothelial Growth Factor Receptor-2 / genetics
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Vascular Endothelial Growth Factor Receptor-2 / metabolism*
Substances
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HIF1A protein, human
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Heparan Sulfate Proteoglycans
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Hypoxia-Inducible Factor 1, alpha Subunit
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NFATC Transcription Factors
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NFATC2 protein, human
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PDK1 protein, human
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Peptide Fragments
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Pyruvate Dehydrogenase Acetyl-Transferring Kinase
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VEGFA protein, human
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Vascular Endothelial Growth Factor A
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perlecan
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MTOR protein, human
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Vascular Endothelial Growth Factor Receptor-2
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Protein Serine-Threonine Kinases
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Proto-Oncogene Proteins c-akt
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TOR Serine-Threonine Kinases
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Protein Kinase C
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MAP Kinase Kinase 4