title: Topoisomerase II-mediated DNA cleavage by amonafide and its structural analogs.
abstract: Treatment of SV40-infected monkey cells with amonafide (benzisoquinolinedione), an intercalative antitumor drug, resulted in rapid accumulation of linearized intracellular SV40 DNA molecules that were protein linked. Studies using purified mammalian DNA topoisomerase II have shown that amonafide and its structural analogs interfere with the breakage-rejoining reaction of the enzyme by stabilizing a reversible enzyme-DNA "cleavable complex." Denaturation of the cleavable complex with sodium dodecyl sulfate resulted in DNA cleavage and the covalent association of topoisomerase II polypeptides with the cleaved DNA. Unwinding measurements indicate that amonafide is a DNA intercalator. These results suggest that amonafide and its structural analogs (e.g., mitonafide) represent a new class of intercalative topoisomerase II-active antitumor drugs. Different from other topoisomerase II-active antitumor drugs, amonafide and mitonafide induce specific DNA cleavage at a single major site on pBR322 DNA. The strong site specificity of amonafide may allow detailed characterization of the intercalator-stabilized, topoisomerase II-DNA cleavable complex.
authors.affiliation: Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
authors.forename: Y H
authors.initials: YH
authors.lastname: Hsiang
authors.forename: J B
authors.initials: JB
authors.lastname: Jiang
authors.forename: L F
authors.initials: LF
authors.lastname: Liu
mesh_terms: D000225:Adenine; D000818:Animals; D002460:Cell Line; D004249:DNA Damage; D004250:DNA Topoisomerases, Type II / Q000378:metabolism; D004279:DNA, Viral / Q000378:metabolism* / Q000648:ultrastructure; D000882:Haplorhini; D007094:Imides; D066298:In Vitro Techniques; D007364:Intercalating Agents; D007546:Isoquinolines / Q000494:pharmacology*; D053644:Naphthalimides; D009690:Nucleic Acid Conformation; D063065:Organophosphonates; D013539:Simian virus 40; D013329:Structure-Activity Relationship; D059005:Topoisomerase II Inhibitors
chemical_list: D004279:DNA, Viral; D007094:Imides; D007364:Intercalating Agents; D007546:Isoquinolines; D053644:Naphthalimides; D063065:Organophosphonates; D059005:Topoisomerase II Inhibitors; C019215:mitonafide; C037020:amonafide; D004250:DNA Topoisomerases, Type II; D000225:Adenine