Nitiss J L, Zhou J, Rose A, Hsiung Y, Gale K C, Osheroff N
Molecular Pharmacology Department, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA.
Biochemistry. 1998 Mar 3;37(9):3078-85. doi: 10.1021/bi9723257.
DMP 840 ((R,R)-2,2'-[1,2-ethanediylbis[imino(1-methyl-2, 1-ethanediyl)]-bis(5-nitro-1H-benz[de]isoquinoline-1,3(2H)-dione] dimethanesulfonate) is a novel bis(naphthalimide) that has shown promising antitumor activity in a variety of preclinical model systems. The compound binds to DNA with high affinity and intercalates, but the mechanism of cell killing has not been elucidated. We have used yeast strains to test whether DMP-840 is active against either topoisomerase I or II. We found that temperature-sensitive top2 mutants resistant to etoposide or amsacrine also confer resistance to DMP-840. In addition, cells overexpressing yeast topoisomerase II were hypersensitive to the drug. By contrast, top1 deletions rendered cells hypersensitive to the drug. These results strongly suggest that DMP-840 acts against eukaryotic topoisomerase II and kills cells by converting the enzyme into a cellular poison. We verified that DMP-840 is active against eukaryotic topoisomerase II by demonstrating that the drug stimulates formation of a cleavage complex with purified yeast topoisomerase II in vitro. We also demonstrated that the drug is active against human topoisomerase II by showing that expression of human topoisomerase II restored sensitivity of resistant yeast cells to DMP-840. We have also directly demonstrated that DMP-840 acts as a poison against purified human topoisomerase II alpha. Taken together, these results indicate that DMP-840 acts like other intercalating topoisomerase II poisons; it kills eukaryotic cells by stabilizing the cleavage complex of topoisomerase II with DNA.
DMP 840（(R,R)-2,2'-[1,2 - 乙二基双[亚氨基(1 - 甲基 - 2,1 - 乙二基)] - 双(5 - 硝基 - 1H - 苯并[de]异喹啉 - 1,3(2H)-二酮]二甲磺酸盐）是一种新型双萘酰亚胺，在多种临床前模型系统中已显示出有前景的抗肿瘤活性。该化合物以高亲和力与DNA结合并嵌入其中，但细胞杀伤机制尚未阐明。我们使用酵母菌株来测试DMP - 840对拓扑异构酶I或II是否有活性。我们发现对依托泊苷或安吖啶耐药的温度敏感型top2突变体也对DMP - 840耐药。此外，过表达酵母拓扑异构酶II的细胞对该药物高度敏感。相比之下，top1缺失使细胞对该药物高度敏感。这些结果强烈表明DMP - 840作用于真核拓扑异构酶II，并通过将该酶转化为细胞毒素来杀死细胞。我们通过证明该药物在体外刺激纯化的酵母拓扑异构酶II形成裂解复合物，验证了DMP - 840对真核拓扑异构酶II有活性。我们还通过表明人拓扑异构酶II的表达恢复了耐药酵母细胞对DMP - 840的敏感性，证明了该药物对人拓扑异构酶II有活性。我们还直接证明了DMP - 840对纯化的人拓扑异构酶IIα起毒素作用。综上所述，这些结果表明DMP - 840的作用方式与其他嵌入型拓扑异构酶II毒素类似；它通过稳定拓扑异构酶II与DNA的裂解复合物来杀死真核细胞。
