Characteristic effect of an anticancer dinuclear platinum(II) complex on the higher-order structure of DNA
Characteristic effect of an anticancer dinuclear platinum(II) complex on the higher-order structure of DNA
复制标题
DOI：
10.1007/s00775-010-0637-y
复制
发表时间：
2010-06-01
影响因子：
3
通讯作者：
Yoshikawa, Kenichi
中科院分区：
文献类型：
--
作者：
Kida, Naoko;Katsuda, Yousuke;Yoshikawa, Kenichi
已知1，2，3-三唑根桥联双核铂（II）配合物[{cis-Pt（NH3）（2）}（2）（A μ-OH）（A μ-1，2，3-ta-N（1），N（2））]（NO3）（2）（AMTA）对几种人肿瘤细胞系显示出高的体外细胞毒性，并避免了对顺铂的交叉耐药性。在本研究中，我们研究了AMTA的剂量和时间依赖性的影响上的一个大的DNA，T4噬菌体DNA（166 kbp）的高阶结构，通过调整单分子观察与荧光显微镜。发现AMTA诱导DNA收缩成紧密状态，其效力比顺铂高得多。通过对溶液中单个DNA分子的布朗运动进行定量分析，可以清楚地看出，处于致密状态的DNA片段的密度比不存在AMTA时的密度大约2，000倍。圆二色光谱表明AMTA引起DNA二级结构从B型向C型转变，其特征在于快速和缓慢的过程。电泳测量表明，AMTA的超螺旋DNA的结合诱导解旋的双螺旋。我们的研究结果表明，AMTA作用于DNA通过静电相互作用和配位结合;前者导致快速变化的二级结构从B的C形式，而后者促进收缩的高阶结构作为一个相对缓慢的动力学过程。AMTA对DNA的收缩效应可归因于DNA分子上沿着的桥数目的可能增加。可以得出结论，AMTA与DNA的相互作用的方式显着不同的顺铂。
It is known that a 1,2,3-triazolato-bridged dinuclear platinum(II) complex, [{cis-Pt(NH3)(2)}(2)(A mu-OH)(A mu-1,2,3-ta-N (1),N (2))](NO3)(2) (AMTA), shows high in vitro cytotoxicity against several human tumor cell lines and circumvents cross-resistance to cisplatin. In the present study, we examined a dose- and time-dependent effect of AMTA on the higher-order structure of a large DNA, T4 phage DNA (166 kbp), by adapting single-molecule observation with fluorescence microscopy. It was found that AMTA induces the shrinking of DNA into a compact state with a much higher potency than cisplatin. From a quantitative analysis of the Brownian motion of individual DNA molecules in solution, it became clear that the density of a DNA segment in the compact state is about 2,000 times greater than that in the absence of AMTA. Circular dichroism spectra suggested that AMTA causes a transition from the B to the C form in the secondary structure of DNA, which is characterized by fast and slow processes. Electrophoretic measurements indicated that the binding of AMTA to supercoiled DNA induces unwinding of the double helix. Our results indicate that AMTA acts on DNA through both electrostatic interaction and coordination binding; the former causes a fast change in the secondary structure from the B to the C form, whereas the latter promotes shrinking in the higher-order structure as a relatively slow kinetic process. The shrinking effect of AMTA on DNA is attributable to the possible increase in the number of bridges along a DNA molecule. It is concluded that AMTA interacts with DNA in a manner markedly different from that of cisplatin.