The DRAG test: an assay for detection of genotoxic damage

A high throughput assay (the DRAG test) is described, which could be a usef ul tool for the detection of repairable DNA adducts, sind which is based on the inhibition of the growth of DNA repair-deficient Chinese hamster ovary (CHO) cells. The cytotoxicity of a test substance towards DNA repair-defic ient CHO cell lines is compared with the corresponding cytotoxicity in the parental wild-type CHO cell line (AA8). A more pronounced toxicity toward a DNA repair-deficient cell line is interpreted as being the consequence of its inability to repair the DNA adduct induced by the compound. (+)-7 beta ,8 alpha -Dihydroxy-9 alpha ,10 alpha -epoxy-7,8,9,10- tetrahydrobenzo[alph a ]pyrene, camptothecin, ethyl methanesulphonate and mitomycin C were used as reference substances, and the overall results indicate that the DRAG tes t could be useful in the screening of compounds for the production of repai rable DNA adducts. The main advantages with the DRAG test are that it provi des a relevant endpoint, it is rapid, it requires small amounts of the test item, and it permits a large number of compounds to be tested.