title: Regulation of cyclooxygenase and 12-lipoxygenase catalysis by phospholipid hydroperoxide glutathione peroxidase in A431 cells.
abstract: Regulation of arachidonate metabolism in human epidermoid carcinoma A431 cells by phospholipid hydroperoxide glutathione peroxidase (PHGPx) and cytosolic glutathione peroxidase (GPx1) was studied. In order to study the effect of reduced glutathione (GSH) on the catalysis regulation of these oxygenation enzymes, diethyl maleate was used to deplete the intracellular GSH. In the presence of 13-hydroperoxyoctadecadienoic acid, the enzymatic catalysis of cyclooxygenase and 12-lipoxygenase was significantly increased in the GSH-depleted cells. In terms of the inhibitory effect on 12-lipoxygenase, PHGPx was more sensitive to GSH concentrations than GPx1. Inhibition of PHGPx activity by the treatment of cells with antisense oligonucleotide of PHGPx mRNA increased the enzymatic catalysis of both cyclooxygenase and 12-lipoxygenase. In conclusion, the results indicate that catalysis of cyclooxygenase and 12-lipoxygenase in A431 cells was regulated by redox-reaction, and PHGPx seems to play an important role in the controlling of these reactions.
authors.affiliation: Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, Taiwan, Republic of China.
authors.forename: C J
authors.initials: CJ
authors.lastname: Chen
authors.forename: H S
authors.initials: HS
authors.lastname: Huang
authors.forename: S B
authors.initials: SB
authors.lastname: Lin
authors.forename: W C
authors.initials: WC
authors.lastname: Chang
mesh_terms: D001092:Arachidonate 12-Lipoxygenase / Q000378:metabolism*; D016718:Arachidonic Acid / Q000378:metabolism; D001792:Blood Platelets / Q000201:enzymology / Q000378:metabolism; D002294:Carcinoma, Squamous Cell; D002384:Catalysis; D002458:Cell Fractionation; D005978:Glutathione / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D006801:Humans; D050356:Lipid Metabolism; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D010084:Oxidation-Reduction; D000080662:Phospholipid Hydroperoxide Glutathione Peroxidase; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D014407:Tumor Cells, Cultured
chemical_list: D016376:Oligonucleotides, Antisense; D016718:Arachidonic Acid; D000080662:Phospholipid Hydroperoxide Glutathione Peroxidase; D005979:Glutathione Peroxidase; D001092:Arachidonate 12-Lipoxygenase; D011451:Prostaglandin-Endoperoxide Synthases; D005978:Glutathione