Faculty Collaboration Database

Hyperresistance to cholesterol hydroperoxide-induced peroxidative injury and apoptotic death in a tumor cell line that overexpresses glutathione peroxidase isotype-4. Free Radic Biol Med 2001 Nov 01;31(9):1051-65

Date

10/26/2001

Pubmed ID

11677038

DOI

10.1016/s0891-5849(01)00685-2

Scopus ID

2-s2.0-0035501073 (requires institutional sign-in at Scopus site)   60 Citations

Abstract

The selenoenzyme phospholipid hydroperoxide glutathione peroxidase (PHGPX; GPX4) plays a key role in eukaryotic defense against potentially lethal peroxidative injury and also regulation of physiological peroxide tone. In this work we focused on the cytoprotective antiperoxidant effects of GPX4, using a breast tumor epithelial cell line that over-expresses the enzyme. Wild-type COH-BR1 cells, which exhibit little (if any) GPX4 activity, were transfected with a construct encoding the mitochondrion-targeted long (L) form of the enzyme. Several transfectant clones were selected which expressed relatively large amounts of GPX4, as determined by both Northern and Western analysis. Enzyme activity ranged from 15-fold to 190-fold greater than that of wild-type or null-transfected cells. The functional ramifications of GPX4 overexpression were tested by challenging cells with photochemically generated cholesterol hydroperoxides (ChOOHs) in liposomal form. Compared with vector controls, overexpressing clones were found to be substantially more resistant to ChOOH-induced killing, as determined by annexin-V (early apoptotic) and thiazolyl blue (mitochondrial dehydrogenase) reactivity. Concomitantly, the clones exhibited a striking hyper-resistance to free radical-mediated lipid peroxidation, as assessed by labeling cell membranes with [(14)C]cholesterol and measuring a family of radiolabeled oxidation products (ChOX). L-form GPX4's antiperoxidant and cytoprotective effects could reflect its ability to detoxify ChOOHs as they enter cells and/or cell-derived lipid hydroperoxides arising from ChOOH one-electron turnover.

Author List

Hurst R, Korytowski W, Kriska T, Esworthy RS, Chu FF, Girotti AW

Author

Tamas Kriska PhD Research Scientist I in the Pharmacology and Toxicology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Animals
Apoptosis
Breast Neoplasms
Cholesterol
Glutathione Peroxidase
Humans
Isoenzymes
Lipid Peroxidation
Oxidative Stress
Rats
Transfection
Tumor Cells, Cultured
Up-Regulation