Dna binding and its relationship to carcinogenesis by different polycyclic hydrocarbons

Five different polycyclic hydrocarbons with different degrees of carcinogenicity in vivo were tested for their metabolism to water-soluble products and their binding to DNA, RNA, and protein in normal embryonic hamster and BHK cells. The compounds studied were 7, 12-dimethylbenz(a)anthracene, benzo(a)pyrene, 20-methyl-cholanthrene, dibenz(a,h)anthracene and dibenz(a,c)anthracene. All five compounds were metabolized to water-soluble produces in both types of cells and treatment of cells with aminophylline enhanced this metabolism. After and not before this enhancement of metabolism by aminophylline, there was a relationship between the degree of carcinogenicity and binding to DNA. There was no such relationship with binding to RNA or protein. The results, indicating a relationship between the degree of carcinogenicity and binding to DNA under appropriate conditions of metabolism, support the suggestion that DNA is the target for carcinogenesis by such carcinogens.