Tags

Type your tag names separated by a space and hit enter

Removal of glutathione produces apoptosis and necrosis in HepG2 cells overexpressing CYP2E1.
Alcohol Clin Exp Res. 2001 Apr; 25(4):619-28.AC

Abstract

BACKGROUND

Previous studies have shown that addition of ethanol, iron, or arachidonic acid to HepG2 cells expressing CYP2E1 produced a loss in cell viability and caused apoptosis. These effects were enhanced when cellular reduced glutathione (GSH) levels were lowered by treatment with buthionine sulfoximine (BSO). Overexpression of CYP2E1 in HepG2 cells could produce toxicity even in the absence of added toxin after BSO treatment. Studies were carried out to characterize this CYP2E1-and BSO-dependent toxicity.

METHODS

HepG2 cells expressing CYP2E1 were treated with BSO for 1 to 4 days, and various parameters associated with apoptosis and cell viability were assayed.

RESULTS

Treatment of cells expressing CYP2E1 (E47 cells) with BSO resulted in apoptosis as well as necrosis. The apoptosis and necrosis were independent of each other. No toxicity was found with control HepG2 cells or HepG2 cells expressing CYP3A4 instead of CYP2E1 under these conditions. The antioxidant trolox partially prevented the apoptosis and necrosis, whereas diallylsulfide, a CYP2E1 inhibitor, was fully protective. The activity of caspase 3, but not caspases 1, 8, or 9, was increased in the BSO-treated E47 cells, and an inhibitor of caspase 3 prevented apoptosis. Damage to mitochondria appears to play a role in the CYP2E1- and BSO-dependent toxicity, because mitochondrial membrane potential was decreased and cyclosporin A, an inhibitor of the mitochondrial membrane permeability transition, prevented the apoptosis and the necrosis. The fall in membrane potential was prevented by trolox and diallylsulfide, suggesting damage to the mitochondria by CYP2E1-derived reactive oxygen species.

CONCLUSIONS

These results indicate the critical role of GSH in protecting against CYP2E1-mediated oxidative stress and that mitochondria may be a target for CYP2E1-derived reactive oxygen species, and suggest that interactions between CYP2E1, mitochondria, and altered GSH homeostasis may play a role in alcohol-induced liver injury.

Authors+Show Affiliations

Department of Biochemistry and Molecular Biology, Mount Sinai School of Medicine, New York, New York, USA.No affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

11329505

Citation

Wu, D, and A I. Cederbaum. "Removal of Glutathione Produces Apoptosis and Necrosis in HepG2 Cells Overexpressing CYP2E1." Alcoholism, Clinical and Experimental Research, vol. 25, no. 4, 2001, pp. 619-28.
Wu D, Cederbaum AI. Removal of glutathione produces apoptosis and necrosis in HepG2 cells overexpressing CYP2E1. Alcohol Clin Exp Res. 2001;25(4):619-28.
Wu, D., & Cederbaum, A. I. (2001). Removal of glutathione produces apoptosis and necrosis in HepG2 cells overexpressing CYP2E1. Alcoholism, Clinical and Experimental Research, 25(4), 619-28.
Wu D, Cederbaum AI. Removal of Glutathione Produces Apoptosis and Necrosis in HepG2 Cells Overexpressing CYP2E1. Alcohol Clin Exp Res. 2001;25(4):619-28. PubMed PMID: 11329505.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Removal of glutathione produces apoptosis and necrosis in HepG2 cells overexpressing CYP2E1. AU - Wu,D, AU - Cederbaum,A I, PY - 2001/5/1/pubmed PY - 2001/6/15/medline PY - 2001/5/1/entrez SP - 619 EP - 28 JF - Alcoholism, clinical and experimental research JO - Alcohol Clin Exp Res VL - 25 IS - 4 N2 - BACKGROUND: Previous studies have shown that addition of ethanol, iron, or arachidonic acid to HepG2 cells expressing CYP2E1 produced a loss in cell viability and caused apoptosis. These effects were enhanced when cellular reduced glutathione (GSH) levels were lowered by treatment with buthionine sulfoximine (BSO). Overexpression of CYP2E1 in HepG2 cells could produce toxicity even in the absence of added toxin after BSO treatment. Studies were carried out to characterize this CYP2E1-and BSO-dependent toxicity. METHODS: HepG2 cells expressing CYP2E1 were treated with BSO for 1 to 4 days, and various parameters associated with apoptosis and cell viability were assayed. RESULTS: Treatment of cells expressing CYP2E1 (E47 cells) with BSO resulted in apoptosis as well as necrosis. The apoptosis and necrosis were independent of each other. No toxicity was found with control HepG2 cells or HepG2 cells expressing CYP3A4 instead of CYP2E1 under these conditions. The antioxidant trolox partially prevented the apoptosis and necrosis, whereas diallylsulfide, a CYP2E1 inhibitor, was fully protective. The activity of caspase 3, but not caspases 1, 8, or 9, was increased in the BSO-treated E47 cells, and an inhibitor of caspase 3 prevented apoptosis. Damage to mitochondria appears to play a role in the CYP2E1- and BSO-dependent toxicity, because mitochondrial membrane potential was decreased and cyclosporin A, an inhibitor of the mitochondrial membrane permeability transition, prevented the apoptosis and the necrosis. The fall in membrane potential was prevented by trolox and diallylsulfide, suggesting damage to the mitochondria by CYP2E1-derived reactive oxygen species. CONCLUSIONS: These results indicate the critical role of GSH in protecting against CYP2E1-mediated oxidative stress and that mitochondria may be a target for CYP2E1-derived reactive oxygen species, and suggest that interactions between CYP2E1, mitochondria, and altered GSH homeostasis may play a role in alcohol-induced liver injury. SN - 0145-6008 UR - https://www.unboundmedicine.com/medline/citation/11329505/Removal_of_glutathione_produces_apoptosis_and_necrosis_in_HepG2_cells_overexpressing_CYP2E1_ L2 - http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=11329505.ui DB - PRIME DP - Unbound Medicine ER -