title: Genetic damage, but limited evidence of oxidative stress markers in diethyl maleate-induced glutathione depleted mouse lymphoma L5178Y (TK(+/-)) cell cultures.
abstract: Depletion of glutathione (GSH) in cells exposed to certain xenobiotics has been proposed to result in oxidative stress, which could lead to damage of cellular macromolecules such as proteins, lipids, and DNA. Diethyl maleate (DEM) is known to conjugate with GSH and rapidly lower cellular GSH levels. The objective of this study was to investigate the influence of DEM-induced GSH depletion on various genotoxicity and gene expression end points in mouse lymphoma L5178Y (TK(+/-)) cell cultures. Cells were exposed to DEM for 4 h at concentrations of 0, 6.7, 13.5, 26.9, 53.8, 107.6, 215.3, and 430.6 µg/mL (0.039-2.5 mM). Genotoxicity was evaluated by examining the induction of in vitro micronuclei (20 h post-treatment) and DNA strand breaks as measured by comet (immediately following treatment), and correlating these observations to cellular GSH levels. In the current study, GSH was decreased more than 50% at the lowest test concentration (6.7 µg/mL) and more than 95% at ≥ 107.6 µg/mL. A significant increase in micronuclei and DNA strand breaks was observed at concentrations of ≥ 26.9 µg/mL. Gene expression of seven apoptosis and oxidative-stress related genes showed significant alterations in only three genes only at the highest test concentration. Quantifiable levels of 8-OH-dG (≥ 2 adducts per 1 × 10(8) NT) were not detected at any treatment concentration. These results demonstrate an association between DEM-induced genotoxicity and GSH depletion in mouse lymphoma L5178Y (TK(+/-)) cells, but not with other oxidative markers.
authors.affiliation: Toxicology and Environmental Research & Consulting, The Dow Chemical Company, Midland, Michigan, USA.
authors.forename: David R
authors.initials: DR
authors.lastname: Geter
authors.forename: Fagen
authors.initials: F
authors.lastname: Zhang
authors.forename: Melissa R
authors.initials: MR
authors.lastname: Schisler
authors.forename: Amanda J
authors.initials: AJ
authors.lastname: Wood
authors.forename: H Lynn
authors.initials: HL
authors.lastname: Kan
authors.forename: Yo-Chan
authors.initials: YC
authors.lastname: Jeong
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Bartels
authors.forename: Lisa
authors.initials: L
authors.lastname: McFadden
authors.forename: B Bhaskar
authors.initials: BB
authors.lastname: Gollapudi
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D015415:Biomarkers / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D020552:Comet Assay; D018736:DNA Adducts / Q000378:metabolism; D004249:DNA Damage; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D015870:Gene Expression / Q000187:drug effects; D005978:Glutathione / Q000378:metabolism*; D007940:Leukemia L5178 / Q000473:pathology; D008298:Maleates / Q000633:toxicity*; D051379:Mice; D048629:Micronuclei, Chromosome-Defective / Q000139:chemically induced*; D015162:Micronucleus Tests; D009153:Mutagens / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects* / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D015415:Biomarkers; D018736:DNA Adducts; D008298:Maleates; D009153:Mutagens; D017382:Reactive Oxygen Species; D000080242:8-Hydroxy-2'-Deoxyguanosine; C014476:diethyl maleate; D003849:Deoxyguanosine; D005978:Glutathione