title: Glutathione S-transferases as antioxidant enzymes: small cell lung cancer (H69) cells transfected with hGSTA1 resist doxorubicin-induced apoptosis.
abstract: It has been suggested that the alpha-class glutathione S-transferases (GSTs) protect various cell types from oxidative stress and lipid peroxidation (LPO). In order to examine the protective role of alpha-class GST isozyme hGSTA1-1 against doxorubicin (DOX)-induced lipid peroxidation, cytotoxicity, and apoptosis, human small cell lung cancer (SCLC) H69 cells were stably transfected with hGSTA1. Immunological and biochemical characterization of hGSTA1-transfected cells revealed the expression of functionally active hGSTA1-1 localized near the cellular plasma membranes. hGSTA1-transfected cells acquired significantly increased resistance to the DOX-induced cytotoxicity by suppressing lipid peroxidation levels in these cells. Overexpression of hGSTA1-1 in cells inhibited DOX-mediated depletion of GSH and higher GSH levels were found in DOX-treated hGSTA1-transfected cells as compared with empty vector-transfected controls. hGSTA1-1 overexpression also provided protection to cells from DOX-induced apoptosis by inhibiting phosphorylation of c-Jun-N-terminal kinases (JNK), caspase-3 activation, and by preserving the levels of anti-apoptotic protein Bcl-2. These results are consistent with the idea that the alpha-class GSTs provide protection against oxidative stress by attenuating lipid peroxidation and these enzymes can modulate signaling for apoptosis.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA.
authors.forename: Abha
authors.initials: A
authors.lastname: Sharma
authors.forename: Brad
authors.initials: B
authors.lastname: Patrick
authors.forename: Jie
authors.initials: J
authors.lastname: Li
authors.forename: Rajendra
authors.initials: R
authors.lastname: Sharma
authors.forename: Prince V S
authors.initials: PV
authors.lastname: Jeyabal
authors.forename: Prasada M R V
authors.initials: PM
authors.lastname: Reddy
authors.forename: Sanjay
authors.initials: S
authors.lastname: Awasthi
authors.forename: Yogesh C
authors.initials: YC
authors.lastname: Awasthi
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D017209:Apoptosis / Q000187:drug effects*; D018288:Carcinoma, Small Cell / Q000201:enzymology* / Q000235:genetics / Q000473:pathology*; D045744:Cell Line, Tumor; D004317:Doxorubicin / Q000008:administration & dosage*; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D014162:Transfection
chemical_list: D000975:Antioxidants; D004317:Doxorubicin; C484555:GSTA1 protein, human; D005982:Glutathione Transferase