Mechanism of action of non-cisplatin type DNA-targeted platinum anticancer agents: DNA interactions of novel acridinylthioureas and their platinum conjugates
Mechanism of action of non-cisplatin type DNA-targeted platinum anticancer agents: DNA interactions of novel acridinylthioureas and their platinum conjugates
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DOI：
10.1016/s0006-2952(02)01107-3
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发表时间：
2002-07-15
影响因子：
5.8
通讯作者：
Bierbach, U
中科院分区：
文献类型：
--
作者：
Baruah, H;Rector, CL;Bierbach, U
在无细胞模型体系中，用各种物理化学和生物物理方法研究了两种新型吖啶基硫脲ACR-NH-（CH_2）（2）-C（S）-NHCH_3（1）和ACR-N（CH_3）-C（S）-NHCH_3（3）及其铂偶联物4和5（由[PtCl_2（en）]衍生）与DNA的结合。其中包括：分光光度法药物-DNA滴定、乙锭-DNA荧光猝灭、竞争性药物置换、高分辨率NMR光谱和通过琼脂糖凝胶电泳监测的质粒DNA解旋。吖啶鎓阳离子1显示出与天然DNA的强结合，Ki = 1.5 × 10（6）M-1，排除位点大小（n）为2（吸光度数据的McGhee-von Hippel拟合）。化合物3显示与DNA没有可测量的关联。1的结合比简单的9-甲基氨基吖啶强一个数量级（2）。在交替共聚物中，1表现出轻微的AT偏好。在poly（dA-dT）（2）中，增强的缔合伴随着增加的结合位点（约3bp），而poly（dG-dC）（2）中的参数与经典的嵌入一致。从小牛胸腺DNA偏端霉素1的位移是暗示的非嵌入硫脲在1位于小沟的双链体。用1修饰的d（GGAGCTCC）（2）的H-1 NMR数据表明平面吖啶的插入结合，基于芳族质子信号相对于未结合的1中的芳族质子信号的高场位移（Δ Δ近似为-0.5至-1 ppm）。最后，发现4和5的负超螺旋pUC 19质粒解旋21度和7度/加合物（电泳凝胶迁移率测定）。讨论了4和5的DNA结合模式的差异作为缀合物的明显不同的生物活性的最终来源。(C)2002年爱思唯尔科技有限公司All rights reserved.
The DNA binding of two novel acridinylthioureas, ACR-NH-(CH2)(2)-C(S)-NHCH3 (1) and ACR-N(CH3)-C(S)-NHCH3 (3), and their platinum conjugates 4 and 5-derived from [PtCl2(en)]-was studied in cell-free model systems using various physico-chemical and biophysical methods. These included: spectrophotometric drug-DNA titrations, ethidium-DNA fluorescence quenching, competitive drug displacement, high-resolution NMR spectroscopy, and unwinding of plasmid DNA monitored by agarose gel electrophoresis. The acridinium cation of 1 showed strong binding to native DNA with K-i = 1.5 x 10(6) M-1 and an excluded site size (n) of 2 by (McGhee-von Hippel fits of absorbance data). Compound 3 showed no measurable association with DNA. Binding of 1 was an order of magnitude stronger than that of simple 9-methylaminoacridine (2). In alternating copolymers, 1 exhibited slight AT preference. In poly(dA-dT)(2), enhanced association was accompanied by an increased binding site (approximately 3 bp), while parameters in poly(dG-dC)(2) were consistent with classical intercalation. Displacement of 1 by distamycin from calf thymus DNA was suggestive of non-intercalating thiourea in 1 being located in the minor groove of the duplex. H-1 NMR data of d(GGAGCTCC)(2) modified with 1 indicated intercalative binding of planar acridine, based on upfield shifts of aromatic proton signals relative to those in unbound 1 (Deltadelta approximate to -0.5 to -1 ppm). Finally, 4 and 5 were found to unwind negatively supercoiled pUC19 plasmid by 21degrees and 7degrees per adduct, respectively (electrophoretic gel mobility assays). The difference in DNA binding modes of 4 and 5 is discussed as the ultimate source of the distinctly different biological activities of the conjugates. (C) 2002 Elsevier Science Inc. All rights reserved.