Inhibition of arachidonate metabolism in human epidermoid carcinoma a431 cells overexpressing phospholipid hydroperoxide glutathione peroxidase.

Abstract

Phospholipid hydroperoxide glutathione peroxidase (PHGPx), a selenium-dependent glutathione peroxidase, can interact with lipophilic substrates, including phospholipid hydroperoxides, fatty acid hydroperoxides and cholesterol hydroperoxides, and can reduce them to hydroxide compounds. It also seems to be a major regulator of lipid oxygenation in human epidermoid carcinoma A431 cells. In order to study the functional role of PHGPx in the regulation of 12-lipoxygenase and cyclooxygenase, cDNA of PHGPx was inserted into pcDNA3.1/His, and a plasmid designated as S4 with the His-tag sequence inserted between PHGPx and its 3'-untranslated region was constructed. A number of stable transfectants of A431 cells that could express the tag-PHGPx were generated using plasmid S4. Using an intact cell assay system, the metabolism of arachidonic acid to prostaglandin E(2) significantly decreased in stable transfectants of overexpressing PHGPx compared to that in a vector control cell line. If the intact cell assay was carried out in the presence of 13-hydroperoxyoctadecadienoic acid as a stimulator of lipid peroxidation, formation of 12-hydroxyeicosatetraenoic acid from arachidonic acid also significantly decreased in stable transfectants of overexpressing PHGPx compared to that in a vector control cell line, indicating that PHGPx could downregulate the 12-lipoxygenase activity in cells. These results support the hypothesis that PHGPx plays a pivotal role in the regulation of arachidonate metabolism in A431 cells.

• Authors: Ching-Jiunn Chen, Huei-Sheng Huang, Wen-Chang Chang
• Journal: Journal of biomedical science (J Biomed Sci) 2002 Sep-Oct Vol. 9 Issue 5 Pg. 453-9 ISSN: 1021-7770 [Print] England
• PMID: 12218361 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright 2002 National Science Council, ROC and S. Karger AG, Basel

Chemical References

• DNA Primers
• Arachidonic Acid
• Phospholipid Hydroperoxide Glutathione Peroxidase
• Glutathione Peroxidase
• Oxygen

Topics

• Arachidonic Acid (antagonists & inhibitors, metabolism)
• Base Sequence
• Blotting, Western
• DNA Primers
• Glutathione Peroxidase (metabolism)
• Humans
• Oxygen (metabolism)
• Phospholipid Hydroperoxide Glutathione Peroxidase
• Transfection
• Tumor Cells, Cultured