Hsiang Y H, Jiang J B, Liu L F
Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
Mol Pharmacol. 1989 Sep;36(3):371-6.
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.
用氨萘非特（苯并异喹啉二酮），一种嵌入型抗肿瘤药物，处理感染SV40的猴细胞，导致细胞内与蛋白质相连的线性化SV40 DNA分子迅速积累。使用纯化的哺乳动物DNA拓扑异构酶II进行的研究表明，氨萘非特及其结构类似物通过稳定可逆的酶-DNA“可切割复合物”来干扰该酶的断裂-重连反应。用十二烷基硫酸钠使可切割复合物变性导致DNA切割以及拓扑异构酶II多肽与切割后的DNA共价结合。解旋测量表明氨萘非特是一种DNA嵌入剂。这些结果表明氨萘非特及其结构类似物（如米托萘非特）代表了一类新型的嵌入型拓扑异构酶II活性抗肿瘤药物。与其他拓扑异构酶II活性抗肿瘤药物不同，氨萘非特和米托萘非特在pBR322 DNA上的单个主要位点诱导特异性DNA切割。氨萘非特的强位点特异性可能允许对嵌入剂稳定的拓扑异构酶II-DNA可切割复合物进行详细表征。
