Endorepellin affects angiogenesis by antagonizing diverse vascular endothelial growth factor receptor 2 (VEGFR2)-evoked signaling pathways: transcriptional repression of hypoxia-inducible factor 1α and VEGFA and concurrent inhibition of nuclear factor of activated T cell 1 (NFAT1) activation.
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.
Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
Atul
A
Goyal
Chiara
C
Poluzzi
Chris D
CD
Willis
James
J
Smythies
Adam
A
Shellard
Thomas
T
Neill
Renato V
RV
Iozzo
D021581:Active Transport, Cell Nucleus / Q000502:physiology; D000818:Animals; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D019812:Heparan Sulfate Proteoglycans / Q000235:genetics / Q000378:metabolism*; D061307:Human Umbilical Vein Endothelial Cells / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism*; D048670:MAP Kinase Kinase 4 / Q000235:genetics / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000502:physiology*; D050778:NFATC Transcription Factors / Q000235:genetics / Q000378:metabolism*; D018919:Neovascularization, Physiologic / Q000502:physiology*; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism; D011493:Protein Kinase C / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism; D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D013552:Swine; D058570:TOR Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000502:physiology*; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000235:genetics / Q000378:metabolism*
D019812:Heparan Sulfate Proteoglycans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D048670:MAP Kinase Kinase 4; D050778:NFATC Transcription Factors; D010446:Peptide Fragments; D019869:Phosphatidylinositol 3-Kinases; D011493:Protein Kinase C; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D058570:TOR Serine-Threonine Kinases; D042461:Vascular Endothelial Growth Factor A; D040301:Vascular Endothelial Growth Factor Receptor-2; C497442:HIF1A protein, human; C494006:NFATC2 protein, human; C000631429:PDK1 protein, human; C467484:VEGFA protein, human; C071927:perlecan; C546842:MTOR protein, human