title: Effects of morpholinyl doxorubicins, doxorubicin, and actinomycin D on mammalian DNA topoisomerases I and II.
abstract: The effect of cyanomorpholinyldoxorubicin, morpholinyldoxorubicin, doxorubicin, and Actinomycin D were studied on purified mouse leukemia (L1210) DNA topoisomerases I and II. DNA unwinding and cross-linking were also studied. It was found that 1) morpholinyldoxorubicin, cyanomorpholinyldoxorubicin, and Actinomycin D (but not doxorubicin) stimulated DNA topoisomerase I-induced cleavage at specific DNA sites; 2) only doxorubicin and Actinomycin D stimulated DNA cleavage by DNA topoisomerase II; 3) at higher drug concentrations, DNA intercalators suppressed enzyme-mediated DNA cleavage induced by DNA topoisomerase I, as well as topoisomerase II; 4) only cyanomorpholinyldoxorubicin produced DNA-DNA cross-links; no DNA unwinding could be observed; and 5) DNA intercalation (unwinding) potency of morpholinyldoxorubicin was about 2-fold less than that of doxorubicin. The data indicate that some DNA intercalators are not only inhibitors of DNA topoisomerase II but act also on DNA topoisomerase I. The stabilization of cleavage intermediates by intercalators may have a common mechanism for DNA topoisomerase I and DNA topoisomerase II.
authors.affiliation: Division of Cancer Treatment, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892.
authors.forename: K
authors.initials: K
authors.lastname: Wassermann
authors.forename: J
authors.initials: J
authors.lastname: Markovits
authors.forename: C
authors.initials: C
authors.lastname: Jaxel
authors.forename: G
authors.initials: G
authors.lastname: Capranico
authors.forename: K W
authors.initials: KW
authors.lastname: Kohn
authors.forename: Y
authors.initials: Y
authors.lastname: Pommier
mesh_terms: D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology*; D002166:Camptothecin / Q000494:pharmacology; D004247:DNA / Q000187:drug effects; D004249:DNA Damage; D003609:Dactinomycin / Q000494:pharmacology*; D004317:Doxorubicin / Q000031:analogs & derivatives* / Q000494:pharmacology*; D051379:Mice; D013329:Structure-Activity Relationship; D059004:Topoisomerase I Inhibitors; D059005:Topoisomerase II Inhibitors
chemical_list: D000903:Antibiotics, Antineoplastic; D059004:Topoisomerase I Inhibitors; D059005:Topoisomerase II Inhibitors; D003609:Dactinomycin; D004317:Doxorubicin; C048396:NSC 354646; D004247:DNA; D002166:Camptothecin