Menadione toxicity in two mouse liver established cell lines having striking genetic differences in quinone reductase activity and glutathione concentrations.
Established cell lines derived from newborn livers of c14CoS/c14CoS and cch/cch mice were examined for differences in menadione toxicity. The 14CoS/14CoS cells exhibit 10-fold higher NAD(P)H:menadione oxidoreductase (NMO1) activity and 3-fold greater concentrations of reduced glutathione (GSH) than the ch/ch cells. In 14CoS/14CoS cells there are also 50% to 3-fold increases in glutathione transferase (GSTA1), UDP glucuronosyltransferase, and the copper, zinc-dependent superoxide dismutase activities. Catalase activity, on the other hand, is six times lower in the 14CoS/14CoS than the ch/ch line. The 14CoS/14CoS cells are two to four times more resistant to menadione killing than ch/ch cells. At concentrations of dicumarol that completely block NMO1 and GSTA1 activities, the 14CoS/14CoS cells show more than twice as much resistance to menadione toxicity than the ch/ch cells. Although superoxide formation is three times higher in untreated 14CoS/14CoS than ch/ch cells, menadione-induced superoxide formation is greater in the dying ch/ch than in the 14CoS/14CoS cells. Cellular resistance to menadione toxicity is correlated with intracellular GSH levels, rather than with the percentage of oxidized glutathione; cytotoxicity is not observed as long as GSH concentrations are sufficiently high (about 5-8 nmol/mg protein). For menadione, the results are consistent with a dominant role of GSH depletion in mediating toxicity and support a protective role for NMO1 activity. This report demonstrates the usefulness of these cell lines as a model system to study mechanisms of oxidative chemically induced toxicity, as well as to understand how intracellular levels of GSH are regulated.
Liu
R M
RM
Department of Environmental Health, University of Cincinnati Medical Center, Ohio 45267-0056.
Nebert
D W
DW
Shertzer
H G
HG
D000818:Animals; D016923:Cell Death / Q000187:drug effects; D002460:Cell Line; D002461:Cell Line, Transformed; D001728:Dicumarol / Q000633:toxicity; D014453:Glucuronosyltransferase / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism*; D005982:Glutathione Transferase / Q000378:metabolism; D008099:Liver / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000235:genetics / Q000378:metabolism*; D010084:Oxidation-Reduction; D013438:Sulfhydryl Compounds / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism; D014812:Vitamin K / Q000633:toxicity*
D013438:Sulfhydryl Compounds; D013481:Superoxides; D014812:Vitamin K; D001728:Dicumarol; D013482:Superoxide Dismutase; D016660:NAD(P)H Dehydrogenase (Quinone); D014453:Glucuronosyltransferase; D005982:Glutathione Transferase; D005978:Glutathione