DNA cross-linking and single-strand breaks induced by teratogenic concentrations of 4-hydroperoxycyclophosphamide and phosphoramide mustard in postimplantation rat embryos.
Postimplantation rat embryos (Day 10) were exposed in vitro to teratogenic concentrations of 4-hydroperoxycyclophosphamide, an activated form of cyclophosphamide, and phosphoramide mustard, the major teratogenic metabolite of cyclophosphamide. Following a 5-h exposure to these agents, drug-induced DNA damage was assessed by alkaline elution. Both drugs induced detectable DNA cross-linking at teratogenic concentrations. Alkaline elution combined with proteinase K digestion indicated that approximately half of the DNA cross-linking was DNA-DNA cross-linking and the other half was DNA-protein cross-linking. In addition to DNA cross-linking, phosphoramide mustard produced DNA strand breaks and/or alkaline labile sites. However, 4-hydroperoxycyclophosphamide did not produce detectable DNA strand breaks or alkaline labile sites. Our data also indicate that the induction of abnormal morphogenesis by 4-hydroperoxycyclophosphamide and phosphoramide mustard is correlated with drug-induced DNA cross-linking.
D000818:Animals; D003520:Cyclophosphamide / Q000031:analogs & derivatives* / Q000494:pharmacology; D004249:DNA Damage; D004277:DNA, Single-Stranded / Q000187:drug effects*; D047108:Embryonic Development; D019286:Endopeptidase K; D005260:Female; D006863:Hydrogen-Ion Concentration; D009690:Nucleic Acid Conformation / Q000187:drug effects*; D010752:Phosphoramide Mustards / Q000494:pharmacology*; D011247:Pregnancy; D051381:Rats; D012697:Serine Endopeptidases / Q000378:metabolism
D004277:DNA, Single-Stranded; D010752:Phosphoramide Mustards; C030090:phosphoramide mustard; D003520:Cyclophosphamide; D012697:Serine Endopeptidases; D019286:Endopeptidase K; C011272:perfosfamide