Interaction of cyclophosphamide with DNA in isolated rat liver cell nuclei.
Isolated rat liver cell nuclei were incubated with the alkylating cytostatic drug cyclophosphamide (CPA) in the presence of a microsomal activation system. Digestion of the 3H-CPA-treated nuclei with DNase I and micrococcal nuclease, respectively, showed that the CPA-modified DNA apparently has become resistant against such enzymatic attack. For analysis of the DNA-CPA reaction products, the DNA was isolated under mild conditions and degraded enzymatically. In cell nuclei whose DNA had been prelabeled with 32P in vivo, a predominant binding of 3H-CPA (about 50%) to the DNA phosphate groups was observed. Terminal phosphate groups apparently play an important role in this reaction. Neutral heating of DNA from 3H-CPA-treated nuclei liberated up to 60% of the initially bound 3H-radioactivity. The results are discussed in relation to the recent data concerning the route of decomposition of activated CPA to phosphoramide mustard and acrolein.
D000818:Animals; D001711:Biotransformation; D002467:Cell Nucleus / Q000378:metabolism*; D003520:Cyclophosphamide / Q000378:metabolism*; D004247:DNA / Q000378:metabolism*; D005260:Female; D066298:In Vitro Techniques; D008099:Liver / Q000378:metabolism*; D010752:Phosphoramide Mustards / Q000378:metabolism; D051381:Rats; D014316:Tritium
D010752:Phosphoramide Mustards; D014316:Tritium; D003520:Cyclophosphamide; D004247:DNA