title: Stabilization of the topoisomerase II-DNA cleavage complex by antineoplastic drugs: inhibition of enzyme-mediated DNA religation by 4'-(9-acridinylamino)methanesulfon-m-anisidide.
abstract: In order to elucidate the mechanism by which the intercalative antineoplastic drug 4'-(9-acridinylamino)methanesulfon-m-anisidide (m-AMSA) stabilizes the covalent topoisomerase II-DNA cleavage complex, the effect of the drug on the DNA cleavage/religation reaction of the type II enzyme from Drosophila melanogaster was examined. At a concentration of 60 microM, m-AMSA enhanced topoisomerase II mediated double-stranded DNA breakage approximately 5-fold. Drug-induced stabilization of the enzyme-DNA cleavage complex was readily reversed by the addition of EDTA or salt. When a DNA religation assay was utilized, m-AMSA was found to inhibit the topoisomerase II mediated rejoining of cleaved DNA approximately 3.5-fold. This result is similar to that previously reported for the effects of etoposide on the activity of the Drosophila enzyme [Osheroff, N. (1989) Biochemistry 28, 6157-6160]. Thus, it appears that structurally disparate classes of topoisomerase II targeted antineoplastic drugs stabilize the enzyme's DNA cleavage complex primarily by interfering with the ability of topoisomerase II to religate DNA.
authors.affiliation: Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146.
authors.forename: M J
authors.initials: MJ
authors.lastname: Robinson
authors.forename: N
authors.initials: N
authors.lastname: Osheroff
mesh_terms: D000585:Aminacrine / Q000031:analogs & derivatives / Q000494:pharmacology*; D000609:Aminoacridines / Q000494:pharmacology*; D000677:Amsacrine / Q000494:pharmacology*; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D046508:Culture Techniques; D004247:DNA / Q000378:metabolism*; D004249:DNA Damage; D004257:DNA Polymerase II / Q000037:antagonists & inhibitors* / Q000378:metabolism; D004250:DNA Topoisomerases, Type II; D004331:Drosophila melanogaster / Q000201:enzymology* / Q000235:genetics; D004795:Enzyme Stability / Q000187:drug effects
chemical_list: D000609:Aminoacridines; D000970:Antineoplastic Agents; D000677:Amsacrine; D000585:Aminacrine; D004247:DNA; D004257:DNA Polymerase II; D004250:DNA Topoisomerases, Type II; C013389:4'-(9-acridinylamino)methanesulfonanilide