title: 15-oxo-Eicosatetraenoic acid, a metabolite of macrophage 15-hydroxyprostaglandin dehydrogenase that inhibits endothelial cell proliferation.
abstract: The formation of 15-oxo-5,8,11,13-(Z,Z,Z,E)-eicosatetraenoic acid (15-oxo-ETE) as a product from rabbit lung 15-hydroxyprostaglandin dehydrogenase (PGDH)-mediated oxidation of 15(S)-hydroperoxy-5,8,11,13-(Z,Z,Z,E)-eicosatetraenoic acid was first reported more than 30 years ago. However, the pharmacological significance of 15-oxo-ETE formation has never been established. We have now evaluated 15-lipoxygenase (LO)-1-mediated arachidonic acid (AA) metabolism to 15-oxo-ETE in human monocytes and mouse RAW macrophages that stably express human 15-LO-1 (R15L cells). A targeted lipidomics approach was used to identify and quantify the oxidized lipids that were formed. 15-oxo-ETE was found to be a major AA-derived LO metabolite when AA was given exogenously or released from endogenous esterified lipid stores by calcium ionophore (CI) calcimycin (A-23187). This established the R15L cells as a useful in vitro model system. Pretreatment of the R15L cells with cinnamyl-3,4-dihydroxycyanocinnamate significantly inhibited AA- or CI-mediated production of 15(S)-hydroperoxy-5,8,11,13-(Z,Z,Z,E)-eicosatetraenoic acid [15(S)-HETE] and 15-oxo-ETE, confirming the role of 15-LO-1 in mediating AA metabolite formation. Furthermore, 15(S)-HETE was metabolized primarily to 15-oxo-ETE. Pretreatment of the R15L cells with the 15-hydroxyprostaglandin dehydrogenase (PGDH) inhibitor 5-[[4-(ethoxycarbonyl)phenyl]azo]-2-hydroxy-benzeneacetic acid (CAY10397) reduced AA- and 15(S)-HETE-mediated formation of 15-oxo-ETE in a dose-dependent manner. This confirmed that macrophage-derived 15-PGDH was responsible for catalyzing the conversion of 15(S)-HETE to 15-oxo-ETE. Finally, 15-oxo-ETE was shown to inhibit the proliferation of human vascular vein endothelial cells by suppressing DNA synthesis, implicating a potential antiangiogenic role. This is the first report describing the biosynthesis of 15-oxo-ETE by macrophage/monocytes and its ability to inhibit endothelial cell proliferation.
authors.affiliation: Center for Cancer Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6160, USA.
authors.forename: Cong
authors.initials: C
authors.lastname: Wei
authors.forename: Peijuan
authors.initials: P
authors.lastname: Zhu
authors.forename: Sumit J
authors.initials: SJ
authors.lastname: Shah
authors.forename: Ian A
authors.initials: IA
authors.lastname: Blair
mesh_terms: D000818:Animals; D001095:Arachidonic Acids / Q000378:metabolism / Q000494:pharmacology*; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects*; D042783:Endothelial Cells / Q000187:drug effects*; D006801:Humans; D006911:Hydroxyprostaglandin Dehydrogenases / Q000378:metabolism*; D008264:Macrophages / Q000201:enzymology*; D051379:Mice; D009000:Monocytes / Q000378:metabolism
chemical_list: D001095:Arachidonic Acids; D006911:Hydroxyprostaglandin Dehydrogenases; C035859:15-hydroxyprostaglandin dehydrogenase