DNA-protein crosslinks induced by exposure of cultured mouse fibroblasts to dibenzo[a,e]fluoranthene and its bay- and pseudo-bay region dihydrodiols.

The presence of DNA-protein crosslinks was shown by the alkaline elution technique in cultured mouse fibroblasts treated with dibenzo[a,e]fluoranthene (DBF), a non-alternating carcinogenic PAH. The crosslinks appeared to be between DNA and protein, since the effect disappeared with proteinase treatment. The crosslinking effect increased with time of exposure to DBF. Two major metabolites of DBF were tested under similar conditions. The pseudo-bay region dihydrodiol of DBF induced similar effects. Its isomer, the bay-region dihydrodiol, was inactive. The possible intervention of a bifunctional metabolite of DBF in the DNA-protein crosslinking process is discussed.