Novel DNA bis-intercalation by MLN944, a potent clinical bisphenazine anticancer drug
Novel DNA bis-intercalation by MLN944, a potent clinical bisphenazine anticancer drug
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DOI：
10.1074/jbc.m404053200
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发表时间：
2004-10-29
影响因子：
4.8
通讯作者：
Yang, DZ
中科院分区：
文献类型：
--
作者：
Dai, JX;Punchihewa, C;Yang, DZ
新型双吩嗪抗癌药物MLN 944是一种新型细胞毒性药物，在体外和体内对一系列人类和小鼠肿瘤模型具有出色的抗肿瘤活性。MLN 944最近已进入I期临床试验。尽管MLN 944与其母体单吩嗪甲酰胺和吖啶甲酰胺抗癌化合物具有结构相似性，但MLN 944似乎通过抑制DNA转录的独特机制而非预期的拓扑异构酶I和II抑制机制发挥作用。在此，我们给出了MLN 944与d（ATG-CAT）2 DNA双链体复合的第一个NMR结构，证明了一种新的结合模式，其中两个吩嗪环在5 '-TpG位点双嵌入，羧酰胺氨基接头位于DNA的大沟中。MLN 944分子在DNA复合物中采用了显著出乎意料的构象和侧链方向，吩嗪环上的N10在pH 7下质子化。MLN 944的吩嗪发色团使用平行碱基堆积嵌入结合模式与侧翼DNA碱基对良好堆积。MLN 944结合的DNA序列特异性和沟识别由与中心G：C碱基对的几种位点特异性氢键相互作用以及与5 '-侧翼胸腺嘧啶的有利堆叠相互作用决定。已知MLN 944的特异性结合位点可被许多重要转录因子识别。我们的电泳凝胶迁移率变动试验结果表明，MLN 944以剂量依赖性方式显著抑制c-Jun DNA与AP-1位点的结合。因此，MLN 944的特殊生物活性可能是由于其新型DNA结合模式导致了独特的作用机制。
The new bisphenazine anticancer drug MLN944 is a novel cytotoxic agent with exceptional anti-tumor activity against a range of human and murine tumor models both in vitro and in vivo. MLN944 has recently entered Phase I clinical trials. Despite the structural similarity with its parent monophenazine carboxamide and acridine carboxamide anticancer compounds, MLN944 appears to work by a distinct mechanism of inhibiting DNA transcription rather than the expected mechanism of topoisomerase I and II inhibition. Here we present the first NMR structure of MLN944 complexed with d(ATG-CAT) 2 DNA duplex, demonstrating a novel binding mode in which the two phenazine rings bis-intercalate at the 5'-TpG site, with the carboxamide amino linker lying in the major groove of DNA. The MLN944 molecule adopts a significantly unexpected conformation and side chain orientation in the DNA complex, with the N10 on the phenazine ring protonated at pH 7. The phenazine chromophore of MLN944 is very well stacked with the flanking DNA base pairs using the parallel base-stacking intercalation binding mode. The DNA sequence specificity and the groove recognition of MLN944 binding is determined by several site-specific hydrogen bond interactions with the central G: C base pair as well as the favorable stacking interactions with the 5'-flanking thymine. The specific binding site of MLN944 is known to be recognized by a number of important transcription factors. Our electrophoretic gel mobility shift assay results demonstrated that the c-Jun DNA binding to the AP-1 site is significantly inhibited by MLN944 in a dose-dependent manner. Thus, the exceptional biological activity of MLN944 may be due to its novel DNA binding mode leading to a unique mechanism of action.