MOLECULAR PHARMACOL(XY, 50:728-735 1996). Expression of Human NAD(P)H:Quinone Oxidoreductase (DT-Diaphorase) in Chinese Hamster Ovary Cells: Effect on

Previous studies have indicated that NAD(P)H:quinone oxi-doreductase [DT-diaphorase (NQO1)] plays an important role in the bioreductive activation of quinone-containing antitumor agents. Although these studies demonstrated that purified NQO1 can reduce these compounds in vitro, the importance of NQO1 in the intracellular activation of quinone-containing an-titumor agents remains controversial. In our study, we trans-fected human NQO1 into Chinese hamster ovary cells that do not normally express NQO1 activity and obtained stable clones that expressed NQO1 activity of 1 9-3527 nmol of 2,6-dichlo-rophenolindophenol reduced/mm/mg of protein. The level of NQO1 expression correlated with an increased killing by streptonigrin, EO9 (3-hydroxymethyl-5-aziridinyl-1-methyl-2-(1H-indole-4,7-dione)-propenol), and 2,5-diaziridinyl-3,6-di-methyl-i,4-benzoquinone, but mitomycin C sensitivity was in