Phospholipid Hydroperoxide Glutathione Peroxidase Induces a Delay in G1 of the Cell Cycle

Hong P Wang; Freya Q Schafer; Prabhat C Goswami; Larry W Oberley; Garry R Buettner

doi:10.1080/1071576031000088283

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Phospholipid Hydroperoxide Glutathione Peroxidase Induces a Delay in G1 of the Cell Cycle

Journal article

Peer reviewed

Phospholipid Hydroperoxide Glutathione Peroxidase Induces a Delay in G1 of the Cell Cycle

Hong P Wang, Freya Q Schafer, Prabhat C Goswami, Larry W Oberley and Garry R Buettner

Free radical research, Vol.37(6), pp.621-630

06/01/2003

DOI: 10.1080/1071576031000088283

PMID: 12868489

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Abstract

Phospholipid hydroperoxide glutathione peroxidase (PhGPx) is an antioxidant enzyme that reduces cellular phospholipid hydroperoxides (PLOOHs) to alcohols. Cellular peroxide tone has been implicated in cell growth and differentiation. By reducing the PLOOH level in the cell membrane, PhGPx regulates the peroxide tone and thereby might be involved in cell growth. We hypothesized that overexpression of PhGPx in human breast cancer cells would decrease their growth rate. We stably transfected MCF-7 cells (Wt) with L-PhGPx and measured cell doubling time, plating efficiency, and cell cycle phase transit times. P-4 cells (8-fold increase in PhGPx activity) showed a 2-fold increase in doubling time; doubling time increased directly with PhGPx activity (r=0.95). The higher the PhGPx activity, the lower the plating efficiency (r=-0.86). The profile of other antioxidant enzymes was unchanged. Overexpression of PhGPx lowered the steady-state level of PLOOH (by >60%). Results from bromodeoxyuridine pulse-chase experiments and flow cytometry indicate that PhGPx induced a delay in MCF-7 proliferation that was primarily due to a slower progression from G 1 to S. These results support the hypothesis that PhGPx plays a regulatory role in the progression of MCF-7 cells from G 1 to S possibly by regulating the steady-state levels of PLOOH. These data suggest that PhGPx can lower the peroxide tone, which might change the cellular redox environment resulting in a delay in G 1 transit. Thus, PhGPx could be an important factor in cell growth.

GSH, glutathione

RM, relative movement parameter

TEMED, N,N,N′,N′-tetramethylethylene diamine

PLOOH, phosphatidylcholine hydroperoxide

P-1, P-2, P-3, P-4, are MCF-7 clones stably transfected with PhGPx

PE, plating efficiency

Neo, MCF-7 cells with empty vector

CAT, catalase

Cell cycle

MCF-7, human breast carcinoma cells

LOOHs, lipid hydroperoxides

Lipid hydroperoxide

GPx-1, cytosolic glutathione peroxidase

Glutathione peroxidase

BrdU, bromodeoxyuridine

EtOH, ethanol

PI, propidium iodide

Wt, parental MCF-7 cells

Antioxidant enzymes

MnSOD, manganese superoxide dismutase

PBS, phosphate buffered saline

CuZnSOD, copper zinc superoxide dismutase

SOD, superoxide dismutase

LOH, lipid alcohol

Se-PhGPx, represents the reduced enzyme

EDTA, disodium ethylenediaminetetraacetic acid

GR, glutathione reductase

HO, hydrogen peroxide

GSSG, glutathione disulfide

Se-O-PhGPx, represents the oxidized enzyme

L-PhGPx, mitochondrial phospholipid hydroperoxide glutathione peroxidase

Details

Title: Subtitle: Phospholipid Hydroperoxide Glutathione Peroxidase Induces a Delay in G1 of the Cell Cycle
Creators: Hong P Wang
Freya Q Schafer
Prabhat C Goswami
Larry W Oberley
Garry R Buettner
Resource Type: Journal article
Publication Details: Free radical research, Vol.37(6), pp.621-630
Publisher: Taylor & Francis
DOI: 10.1080/1071576031000088283
PMID: 12868489
ISSN: 1071-5762
eISSN: 1029-2470
Language: English
Date published: 06/01/2003
Academic Unit: Radiation Oncology; Internal Medicine
Record Identifier: 9984047736902771

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