title: 11-Oxoeicosatetraenoic acid is a cyclooxygenase-2/15-hydroxyprostaglandin dehydrogenase-derived antiproliferative eicosanoid.
abstract: Previously, we established that 11(R)-hydroxy-5,8,12,14-(Z,Z,E,Z)-eicosatetraenoic acid (HETE) was a significant cyclooxygenase (COX)-2-derived arachidonic acid (AA) metabolite in epithelial cells. Stable isotope dilution chiral liquid chromatography (LC)-electron capture atmospheric pressure chemical ionization (ECAPCI)/mass spectrometry (MS) was used to quantify COX-2-derived eicosanoids in the human colorectal adenocarcinoma (LoVo) epithelial cell line, which expresses both COX-2 and 15-hydroxyprostaglandin dehydrogenase (15-PGDH). 11(R)-HETE secretion reached peak concentrations within minutes after AA addition before rapidly diminishing, suggesting further metabolism had occurred. Surprisingly, recombinant 15-PGDH, which is normally specific for oxidation of eicosanoid 15(S)-hydroxyl groups, was found to convert 11(R)-HETE to 11-oxo-5,8,12,14-(Z,Z,E,Z)-eicosatetraenoic acid (ETE). Furthermore, LoVo cell lysates converted 11(R)-HETE to 11-oxo-ETE and inhibition of 15-PGDH with 5-[[4-(ethoxycarbonyl)phenyl]azo]-2-hydroxy-benzeneacetic acid (CAY10397) (50 μM) significantly suppressed endogenous 11-oxo-ETE production with a corresponding increase in 11(R)-HETE. These data confirmed COX-2 and 15-PGDH as enzymes responsible for 11-oxo-ETE biosynthesis. Finally, addition of AA to the LoVo cells resulted in rapid secretion of 11-oxo-ETE into the media, reaching peak levels within 20 min of starting the incubation. This was followed by a sharp decrease in 11-oxo-ETE levels. Glutathione (GSH) S-transferase (GST) was found to metabolize 11-oxo-ETE to the 11-oxo-ETE-GSH (OEG)-adduct in LoVo cells, as confirmed by LC-MS/MS analysis. Bromodeoxyuridine (BrdU)-based cell proliferation assays in human umbilical vein endothelial cells (HUVECs) revealed that the half-maximal inhibitory concentration (IC(50)) of 11-oxo-ETE for inhibition of HUVEC proliferation was 2.1 μM. These results show that 11-oxo-ETE is a novel COX-2/15-PGDH-derived eicosanoid, which inhibits endothelial cell proliferation with a potency that is similar to that observed for 15d-PGJ(2).
authors.affiliation: Center for Cancer Pharmacology and Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6160, USA.
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Liu
authors.forename: Suhong
authors.initials: S
authors.lastname: Zhang
authors.forename: Jasbir S
authors.initials: JS
authors.lastname: Arora
authors.forename: Nathaniel W
authors.initials: NW
authors.lastname: Snyder
authors.forename: Sumit J
authors.initials: SJ
authors.lastname: Shah
authors.forename: Ian A
authors.initials: IA
authors.lastname: Blair
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry* / Q000378:metabolism / Q000633:toxicity*; D016718:Arachidonic Acid / Q000737:chemistry / Q000378:metabolism; D001095:Arachidonic Acids / Q000096:biosynthesis* / Q000737:chemistry / Q000633:toxicity; D045744:Cell Line, Tumor; D002851:Chromatography, High Pressure Liquid; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D015777:Eicosanoids / Q000096:biosynthesis / Q000737:chemistry* / Q000633:toxicity*; D005982:Glutathione Transferase / Q000378:metabolism; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects; D006801:Humans; D006911:Hydroxyprostaglandin Dehydrogenases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D013058:Mass Spectrometry; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D013237:Stereoisomerism
chemical_list: C571448:11-oxoeicosatetraenoic acid; D000970:Antineoplastic Agents; D001095:Arachidonic Acids; D015777:Eicosanoids; D011994:Recombinant Proteins; D016718:Arachidonic Acid; D006911:Hydroxyprostaglandin Dehydrogenases; C035859:15-hydroxyprostaglandin dehydrogenase; D051546:Cyclooxygenase 2; D005982:Glutathione Transferase