Epoxyeicosatrienoic Acids and/or Their Metabolites Promote Hypoxic Response of Cells

• Published in: Journal of Pharmacological Sciences Vol. 108; no. 1; pp. 79 - 88
• Main Authors: Suzuki, Sachiko, Oguro, Ami, Osada-Oka, Mayuko, Funae, Yoshihiko, Imaoka, Susumu
• Format: Journal Article
• Language: English
• Published: Japan Elsevier B.V 2008; The Japanese Pharmacological Society; Elsevier
• Subjects: Arachidonic Acid - metabolism; Aryl Hydrocarbon Hydroxylases - biosynthesis; Aryl Hydrocarbon Hydroxylases - genetics; Blotting, Western; Cell Hypoxia - drug effects; Cell Line, Tumor; Cytochrome P-450 CYP2C8; cytochrome P450; dihydroxyeicosatrienoic acid (DHET); Eicosanoids - pharmacology; epoxyeicosatrienoic acid (EET); Erythropoietin - genetics; Humans; hypoxia-inducible factor (HIF); Hypoxia-Inducible Factor 1, alpha Subunit - biosynthesis; Hypoxia-Inducible Factor 1, alpha Subunit - genetics; Luciferases - biosynthesis; Myocytes, Smooth Muscle - drug effects; Myocytes, Smooth Muscle - metabolism; Reverse Transcriptase Polymerase Chain Reaction; vascular endothelial growth factor (VEGF); Vascular Endothelial Growth Factor A - biosynthesis; Vascular Endothelial Growth Factor A - genetics; epoxyeicosatrienoic acid (EET); vascular endothelial growth factor (VEGF); hypoxia-inducible factor (HIF); cytochrome P450; dihydroxyeicosatrienoic acid (DHET)
• ISSN: 1347-8613; 1347-8648
• DOI: 10.1254/jphs.08122FP

Epoxyeicosatrienoic acids (EETs), including 5,6-EET, 8,9-EET, 11,12-EET, and 14,15-EET, are produced by cytochrome P450 (P450) such as CYP2C8 and 2C9; and they are hydrolyzed to dihydroxyeicosatrienoic acids (DHETs) by epoxide hydrolase. Particular interest in the epoxygenase reaction has developed because of the potent biological activities (modulation of vascular tone and anti-inflammatory activity, etc.) attributed to EETs. We focused on a new biological function of EETs and DHETs, which induce vascular endothelial growth factor (VEGF) and erythropoietin (EPO) under hypoxia. Human hepatoma cells, Hep3B, and human umbilical artery endothelial cells (HUAEC) were used in this study. An inhibitor of phospholipase A2, methyl arachidonyl fluorophosphonate (MAFP), and inhibitors of P450s inhibited the VEGF and EPO induction of HUAEC and Hep3B, respectively, under hypoxia. Overexpression of CYP2C8 in Hep3B induced EPO and VEGF under hypoxia. Sulfaphenazole, an inhibitor of CYP2C8/2C9 suppressed luciferase promoter activity with the hypoxia response element (HRE) of VEGF in HUAEC. Exogenous 11,12-EET and 14,15-DHET induced reporter activity in HUAEC and Hep3B cells concomitant with increased levels of hypoxia-inducible factor-1α (HIF-1α), which is a key factor in the hypoxia response, but 11,12-DHET and 14,15-EET did not. These results suggested that EETs and DHETs play an important role in the hypoxia response of cells.