Eo. Ngo et Lm. Nutter, STATUS OF GLUTATHIONE AND GLUTATHIONE-METABOLIZING ENZYMES IN MENADIONE-RESISTANT HUMAN CANCER-CELLS, Biochemical pharmacology, 47(2), 1994, pp. 421-424
Cloned menadione (MD)-resistant human breast cancer cell lines have be
en developed and characterized with respect to glutathione (GSH) conte
nt and GSH-metabolizing enzymes. Increases in the activities of gamma-
glutamyltranspeptidase and glutathione-S-transferase were demonstrated
in the absence of alterations in the GSH content of two cloned MD-res
istant cell lines. The MD-resistant cells also displayed alterations i
n their growth kinetics, possessing longer doubling times and increase
d fractions in the G1/0 phase of the cell cycle as compared to parenta
l MD-sensitive cells. The possible mechanisms for the resistance to MD
, including an increase in repair of MD-induced DNA damage, are discus
sed.