title: 15(S)-hydroxyeicosatetraenoic acid induces angiogenesis via activation of PI3K-Akt-mTOR-S6K1 signaling.
abstract: To determine whether the lipoxygenase metabolites of arachidonic acid, 5(S)-, 12(S)-, and 15(S)-hydroxyeicosatetraenoic acids [5(S)-HETE, 12(S)-HETE, and 15(S)-HETE, respectively] are angiogenic, we have studied their effects on human dermal microvascular endothelial cell (HDMVEC) tube formation and migration. All three HETEs stimulated HDMVEC tube formation and migration. Because 15(S)-HETE was found to be more potent than 5(S)-HETE and 12(S)-HETE in HDMVEC tube formation, we next focused on elucidation of the signaling mechanisms underlying its angiogenic activity. 15(S)-HETE stimulated Akt and S6K1 phosphorylation in HDMVEC in a time-dependent manner. Wortmannin and LY294002, two specific inhibitors of phosphatidylinositol 3-kinase (PI3K), blocked both Akt and S6K1 phosphorylation, whereas rapamycin, a specific inhibitor of Akt downstream effector, mammalian target of rapamycin (mTOR), suppressed only S6K1 phosphorylation induced by 15(S)-HETE suggesting that this eicosanoid activates the PI3K-Akt-mTOR-S6K1 signaling in HDMVEC. Wortmannin, LY294002, and rapamycin also inhibited 15(S)-HETE-induced HDMVEC tube formation and migration. In addition, all three HETEs stimulated angiogenesis as measured by in vivo Matrigel plug assay with 15(S)-HETE being more potent. Pharmacologic inhibition of PI3K-Akt-mTOR-S6K1 signaling completely suppressed 15(S)-HETE-induced in vivo angiogenesis. Consistent with these observations, adenoviral-mediated expression of dominant-negative Akt also blocked 15(S)-HETE-induced HDMVEC tube formation and migration and in vivo angiogenesis. Together, these results show for the first time that 15(S)-HETE stimulates angiogenesis via activation of PI3K-Akt-mTOR-S6K1 signaling.
authors.affiliation: Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA.
authors.forename: Baolin
authors.initials: B
authors.lastname: Zhang
authors.forename: Huiqing
authors.initials: H
authors.lastname: Cao
authors.forename: Gadiparthi N
authors.initials: GN
authors.lastname: Rao
mesh_terms: D002465:Cell Movement / Q000187:drug effects / Q000502:physiology; D003094:Collagen; D004338:Drug Combinations; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects; D004789:Enzyme Activation; D006801:Humans; D006893:Hydroxyeicosatetraenoic Acids / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000494:pharmacology*; D007797:Laminin; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D011494:Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D011509:Proteoglycans; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt; D038744:Ribosomal Protein S6 Kinases, 90-kDa / Q000378:metabolism*; D015398:Signal Transduction; D012867:Skin / Q000098:blood supply*; D058570:TOR Serine-Threonine Kinases
chemical_list: D003094:Collagen; D004338:Drug Combinations; D006893:Hydroxyeicosatetraenoic Acids; D007797:Laminin; D019869:Phosphatidylinositol 3-Kinases; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D011509:Proteoglycans; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D038744:Ribosomal Protein S6 Kinases, 90-kDa; D058570:TOR Serine-Threonine Kinases; C059485:matrigel; C025984:15-hydroxy-5,8,11,13-eicosatetraenoic acid; C546842:MTOR protein, human; C494918:AKT1 protein, human; C069329:RPS6KA1 protein, human