ATLA::Alternatives to Laboratory Animals

Volume 29, Number 3

The DRAG test: an assay for detection of genotoxic damage.

ATLA 29, 225-231, May/June 2001

Thomas Helleday,1,2 Fredrik Johansson1 and Dag Jenssen1

1Department of Genetic and Cellular Toxicology, Wallenberg Laboratoty, StockholmUniversity, 106 91 Stockholm, Sweden; 2The Institute for Cancer Studies, University of Sheffield Medical School, Beech Hill Road, Sheffield S10 2RX, UK

SUMMARY

A high throughput assay (the DRAG test) is described, which could be a useful tool for the detection of repairable DNA adducts, and 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-deficient 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. (+)-7β,8a-Dihydroxy-9a,10a-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene, camptothecin, ethyl methanesulphonate and mitomycin C were used as reference substances, and the overall results indicate that the DRAG test could be useful in the screening of compounds for the production of repairable DNA adducts. The main advantages with the DRAG test are that it provides 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.

Keywords: Chinese hamster ovary cells, high throughput assay, DNA repair, DNA damage, DRAG test