Cell culture system for the controlled intracellular generation of reactive oxygen species

The LC(50) of duroquinone was about 25 times lower in a Chinese hamster V79-derived cell line which was genetically engineered for the expression of human cytochrome P-450 reductase (V79-MZ-hOR) than in the parental V79-MZ cell line. Reduction of the O(2) concentration in the atmosphere from 21 to 5% decreased the cytotoxicity of duroquinone by a factor of 4. The addition of duroquinone to the homogenate of V79-MZ-hOR cells led to the formation of Superoxide radicals, as demonstrated by the formation of formazan from nitroblue tetrazolium, and inhibition of this reaction in the presence of Superoxide dismutase. Taken together, these results indicate that the cytotoxicity of duroquinone in V79-MZ-hOR cells is caused by Superoxide [and/or other reactive oxygen species (ROS) formed from Superoxide], In this system, ROS can be formed continuously in a controlled manner within the indicator cells (e.g. by varying the concentrations of O(2) and duroquinone), and the parental V79-MZ cell line can be used as a control.