title: Chemoprotection by 9-aminoacridine derivatives against the cytotoxicity of topoisomerase II-directed drugs.
abstract: The effect of three acridine derivatives, 9-aminoacridine (9AA), 4'-(9-acridinylamino)-methanesulphon-O-anisidide (O-AMSA) and quinacrine were compared in their ability to protect against the cytotoxicity of amsacrine, 9-[[2-methoxy-4-[(methylsulfonyl)amino]phenyl]amino)-N,5-dimethyl-4- acridine-carboxamide (CI-921), N-[2-(dimethylamino)ethyl]acridine-4-carboxamide (AC), etoposide, mitoxantrone and doxorubicin. Cytotoxicity was measured in vitro by clonogenic survival assay and in vivo by life extension assays. All three acridine derivatives protected a Lewis lung cell line in vitro against CI-921, with 9AA having the highest activity. Cellular uptake of [14C] CI-921 by cultured Lewis lung cells was unaffected by 9AA, and slightly stimulated by O-AMSA and quinacrine. 9AA protected Lewis lung cells in vitro against the cytotoxicity of amsacrine, CI-921, AC and etoposide, partially against mitoxantrone but not against doxorubicin. A similar result was obtained with the human melanoma cell line MM96, where 9AA protected against CI-921 but not against doxorubicin toxicity. 9AA protected P388 leukaemia in vivo against amsacrine, CI-921 and AC cytotoxicity, partially against etoposide but not against mitoxantrone or doxorubicin. 9AA also protected against animal toxicity caused by high dose amsacrine and partially against CI-921 toxicity. It is hypothesized that DNA intercalating chemoprotectors act by restricting the conformational flexibility of the DNA and thus the ability of topoisomerase II to form a 'cleavable complex' in which the DNA is covalently linked to the enzyme.
authors.affiliation: Cancer Research Laboratory, University of Auckland Medical School, New Zealand.
authors.forename: G J
authors.initials: GJ
authors.lastname: Finlay
authors.forename: W R
authors.initials: WR
authors.lastname: Wilson
authors.forename: B C
authors.initials: BC
authors.lastname: Baguley
mesh_terms: D000585:Aminacrine / Q000494:pharmacology*; D000609:Aminoacridines / Q000494:pharmacology*; D000677:Amsacrine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D003114:Colony-Forming Units Assay; D007364:Intercalating Agents / Q000494:pharmacology; D007536:Isomerism; D007941:Leukemia P388 / Q000188:drug therapy; D051379:Mice; D011796:Quinacrine / Q000494:pharmacology*; D059005:Topoisomerase II Inhibitors; D014410:Tumor Stem Cell Assay
chemical_list: D000609:Aminoacridines; D000970:Antineoplastic Agents; D007364:Intercalating Agents; D059005:Topoisomerase II Inhibitors; D000677:Amsacrine; C033073:4'-(9-acridinylamino)methanesulfon-o-anisidide; D000585:Aminacrine; D011796:Quinacrine; C042315:asulacrine