Wakelin Laurence P G, Bu Xianyong, Eleftheriou Alexandra, Parmar Alpesh, Hayek Charbel, Stewart Bernard W
School of Medical Sciences, and the School of Women's and Children's Health, University of New South Wales, Sydney 2052, New South Wales, Australia.
J Med Chem. 2003 Dec 18;46(26):5790-802. doi: 10.1021/jm030253d.
We have synthesized a series of bis(9-aminoacridine-4-carboxamides) linked via the 9-position with neutral flexible alkyl chains, charged flexible polyamine chains, and a semirigid charged piperazine-containing chain. The carboxamide side chains comprise N,N-dimethylaminoethyl and ethylmorpholino groups. The compounds are designed to bisintercalate into DNA by a threading mode, in which the side chains are intended to form hydrogen-bonding contacts with the O6/N7 atoms of guanine in the major groove, and the linkers are intended to lie in the minor groove. By this means, we anticipate that they will dissociate slowly from DNA, and be cytotoxic as a consequence of template inhibition of transcription. The dimers remove and reverse the supercoiling of closed circular DNA with helix unwinding angles ranging from 26 degrees to 46 degrees, confirming bifunctional intercalation in all cases, and the DNA complexes of representative members dissociate many orders of magnitude more slowly than simple aminoacridines. Cytotoxicity for human leukemic CCRF-CEM cells was determined, the most active agents having IC(50) values of 35-50 nM in a range extending over 20-fold, with neither the dimethylaminoethyl nor the ethylmorpholino series being intrinsically more toxic. In common with established transcription inhibitors, the morpholino series, with one exception, have no effect on cell cycle distribution in randomly dividing CCRF-CEM populations. By contrast, the dimethylaminoethyl series, with two exceptions, cause G2/M arrest in the manner of topoisomerase poisons, consistent with possible involvement of topoisomerases in their mode of action. Thus, the cellular response to these bisintercalating threading agents is complex and appears to be determined by both their side chain and linker structures. There are no simple relationships between structure, cytotoxicity, and cell cycle arrest, and the origins of this complexity are unclear given that the compounds bind to DNA by a common mechanism.
我们合成了一系列通过9位连接的双（9-氨基吖啶-4-甲酰胺），连接链包括中性柔性烷基链、带电荷的柔性多胺链和含半刚性带电荷哌嗪的链。甲酰胺侧链包含N，N-二甲基氨基乙基和乙基吗啉基团。这些化合物设计为通过穿线模式双插入DNA，其中侧链旨在与大沟中鸟嘌呤的O6/N7原子形成氢键接触，而连接链则位于小沟中。通过这种方式，我们预计它们将从DNA缓慢解离，并由于对转录的模板抑制而具有细胞毒性。这些二聚体能够去除并逆转闭环DNA的超螺旋，解旋角度范围为26度至46度，证实了在所有情况下的双功能插入，并且代表性成员的DNA复合物解离速度比简单氨基吖啶慢许多个数量级。测定了对人白血病CCRF-CEM细胞的细胞毒性，最具活性的药物在20倍的范围内IC(50)值为35 - 50 nM，N，N-二甲基氨基乙基系列和乙基吗啉系列本身都没有更高的毒性。与已有的转录抑制剂一样，除了一个例外，吗啉系列对随机分裂的CCRF-CEM群体中的细胞周期分布没有影响。相比之下，除了两个例外，N，N-二甲基氨基乙基系列以拓扑异构酶毒物的方式导致G2/M期阻滞，这与拓扑异构酶可能参与其作用模式一致。因此，细胞对这些双插入穿线剂的反应是复杂的，似乎由它们的侧链和连接链结构共同决定。结构、细胞毒性和细胞周期阻滞之间没有简单的关系，鉴于这些化合物通过共同机制与DNA结合，这种复杂性的根源尚不清楚。
