Induction of repair synthesis of DNA in mammary and urinary bladder epithelial cells by N-hydroxy derivatives of carcinogenic arylamines.
Unscheduled DNA synthesis (UDS)-inducing activity was used as a parameter to estimate the abilities of rat mammary epithelial cells and urothelial cells from various species to activate carcinogenic aromatic amine derivatives. The N-hydroxy, N-hydroxy-N-acetyl, N-hydroxy-N-glucuronosyl derivatives of 2-aminofluorene (2-AF) and 4-aminobiphenyl (4-ABP) induced UDS in primary cultures of rat mammary epithelial cells, but 2-AF, the O-glucuronide of N-hydroxy-N-acetyl-2-AF (N-OH-AAF) and 4-ABP did not. Neither the activity of N-OH-AAF, N-hydroxy-N-formyl-2-AF, nor N-acetoxy-N-acetyl-2-AF was significantly altered by paraoxon, an inhibitor of microsomal N-deacetylase. Although N-hydroxy-3,2'-dimethyl-4-aminobiphenyl (N-OH-DMABP) also induced UDS, its N-acetyl derivative, which can not be activated by intramolecular, N,O-acetyltransfer, did not. Similarly, rat urothelial cells were responsive to the UDS-inducing activity of this hydroxylamine, but not the hydroxamic acid. In contrast, dog urothelial cells were responsive to both compounds. The UDS-inducing activity of N-OH-AAF was inhibited by paraoxon in the dog, but not in rat urothelial cells. N-Hydroxy-N,N'-diacetylbenzidine induced UDS in the urothelial cells of dog, rat, and rabbit, and a human urothelial cell line, HCV-29, whereas benzidine, N-acetylbenzidine, and N,N'-diacetylbenzidine did not. Co-treatment with 12-O-tetradecanoylphorbol-13-acetate did not enable benzidine to induce UDS in dog urothelial cells. Rat mammary epithelial cells activated N-OH-DMABP by acetyl coenzyme A-dependent O-acetylation and N-OH-AAF by N,O-acetyltransfer. They could not N-deacetylate N-OH-AAF. These results suggest that rat mammary and bladder epithelial cells are capable of activating N-arylhydroxylamine metabolites of these carcinogens, probably by N,O-acetyltransfer and O-acetylation, whereas dog urothelial cells are more likely to activate these metabolites by N-deacetylation and a reaction that has yet to be identified.
Wang
C Y
CY
Department of Chemical Carcinogenesis, Michigan Cancer Foundation, Detroit 48201.
Yamada
H
H
Morton
K C
KC
Zukowski
K
K
Lee
M S
MS
King
C M
CM
D000611:Aminobiphenyl Compounds / Q000494:pharmacology; D000818:Animals; D001560:Benzidines / Q000494:pharmacology; D002273:Carcinogens / Q000494:pharmacology*; D002478:Cells, Cultured; D004260:DNA Repair / Q000187:drug effects*; D004285:Dogs; D004848:Epithelium / Q000187:drug effects; D005260:Female; D005449:Fluorenes / Q000494:pharmacology; D008297:Male; D008321:Mammary Glands, Animal / Q000187:drug effects* / Q000378:metabolism; D010261:Paraoxon / Q000494:pharmacology; D011817:Rabbits; D051381:Rats; D011919:Rats, Inbred Strains; D001743:Urinary Bladder / Q000187:drug effects* / Q000378:metabolism
D000611:Aminobiphenyl Compounds; D001560:Benzidines; D002273:Carcinogens; D005449:Fluorenes; C001042:2',3-dimethyl-4-aminobiphenyl; C006757:4-biphenylamine; C029876:benzidine; C012177:2-aminofluorene; C044345:N-hydroxy-3,2'-dimethyl-4-aminobiphenyl; D010261:Paraoxon