Phosphodiester-Mediated Reaction of Cisplatin with Guanine in Oligodeoxyribonucleotides
Phosphodiester-Mediated Reaction of Cisplatin with Guanine in Oligodeoxyribonucleotides
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DOI：
10.1021/bi801000w
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发表时间：
2008-12-02
期刊：
影响因子：
2.9
通讯作者：
Miller, Paul S.
中科院分区：
文献类型：
--
作者：
Campbell, Meghan A.;Miller, Paul S.
癌症化疗药物顺式二氨二氯铂（II）或顺铂主要与DNA中的鸟嘌呤反应，形成1，2-Pt-GG和1，3-Pt-GNG链内交联，并在较小程度上形成G-G链间交联。最近的NMR证据表明，顺铂也可以与DNA的磷酸二酯核苷酸间键形成配位复合物。我们研究了磷酸二酯骨架对顺铂与缺乏或含有GTG序列的寡脱氧核苷酸反应的影响。顺铂与TpT形成稳定的加合物，可通过反相HPLC分离。顺式-Pt-TpT加合物含有单个Pt，如通过原子吸收光谱法（AAS）和通过电喷雾电离质谱法（ESI-MS）测定的，并且耐蛇毒磷酸二酯酶消化。用氰化钠处理加合物可使TpT再生。当T（pT）（8）用顺铂处理时，观察到类似的加合物形成，但当T（PT）8的磷酸二酯键被甲基膦酸酯基团取代时，则没有观察到。这些结果表明，铂可以与胸腺嘧啶的氧，并可能与磷酸二酯基团的氧协调。如所预期的，含有GTG序列的9聚体与顺铂的反应产生含有1，3-Pt-GTG链内交联的加合物。然而，我们发现，周围的GTG序列的磷酸二酯的数量和位置显着影响链内交联形成。增加寡核苷酸中带负电荷的磷酸二酯的数量增加了GTG铂化的量。用非离子甲基膦酸酯键围绕GTG序列抑制或消除交联形成。这些观察结果表明，顺铂和带负电荷的磷酸二酯骨架之间的相互作用可能在促进DNA中鸟嘌呤核苷酸的铂化中起重要作用。
The cancer chemotherapeutic agent cis-diamminedichloroplatinum(II) or cisplatin reacts primarily with guanines in DNA to form 1,2-Pt-GG and 1,3-Pt-GNG intrastrand cross-links and, to a lesser extent, G-G interstrand cross-links. Recent NMR evidence has suggested that cisplatin can also form a coordination complex with the phosphodiester internucleotide linkage of DNA. We have examined the effects of the phosphodiester backbone on the reactions of cisplatin with oligodeoxyribonucleotides that lack or contain a GTG sequence. Cisplatin forms a stable adduct with TpT that can be isolated by reversed phase HPLC. The cis-Pt-TpT adduct contains a single Pt, as determined by atomic absorption spectroscopy (AAS) and by electrospray ionization mass spectrometry (ESI-MS), and is resistant to digestion by snake venom phosphodiesterase. Treatment of the adduct with sodium cyanide regenerates TpT. Similar adduct formation was observed when T(pT)(8) was treated with cisplatin, but not when the phosphodiester linkages of T(PT)8 were replaced with methylphosphonate groups. These results suggest that the platinum may be coordinated with the oxygens of the thymine and possibly with those of the phosphodiester group. As expected, reaction of a 9-mer containing a GTG sequence with cisplatin yielded an adduct that contained a 1,3-Pt-GTG intrastrand cross-link. However, we found that the number and placement of phosphodiesters surrounding a GTG sequence significantly affected intrastrand cross-link formation. Increasing the number of negatively charged phosphodiesters in the oligonucleotide increased the amount of GTG platination. Surrounding the GTG sequence with nonionic rnethylphosphonate linkages inhibited or eliminated cross-link formation. These observations suggest that interactions between cisplatin and the negatively charged phosphodiester backbone may play an important role in facilitating platination Of guanine nucleotides in DNA.