Frequencies of mutagenic translesion DNA synthesis over cisplatin-guanine intra-strand crosslinks in lacZ plasmids propagated in human cells
Frequencies of mutagenic translesion DNA synthesis over cisplatin-guanine intra-strand crosslinks in lacZ plasmids propagated in human cells
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DOI：
10.1016/j.mrgentox.2014.05.006
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发表时间：
2014-08-01
影响因子：
1.9
通讯作者：
Yagi, Takashi
中科院分区：
文献类型：
--
作者：
Fujikawa, Yoshihiro;Kawanishi, Masanobu;Yagi, Takashi
顺铂（顺二氯二氨铂 (II)）是一种广泛使用的抗癌药物，可形成链间和链内 DNA 交联。主要的链内交联是 1,2-d(GpG) 和 1,3-d(GpNpG) 处的 Pt 加合物（分别为 Pt-GG 和 Pt-GNG）。尽管大多数链内交联被核苷酸切除修复（NER）去除，但剩余的交联可以在染色体复制过程中通过跨损伤DNA合成（TLS）引起突变。为了了解顺铂在人类细胞中诱变的精确机制，在 lacZ 基因中构建了带有单个 Pt-GG 或 1,3-d(GpTpG) 交联 (Pt-GTG) 的质粒，并在 NER 缺陷性干皮病细胞中增殖。从细胞中回收的质粒被引入指示细菌细胞中以获取 TLS 和突变的频率。实验表明，Pt-GTG 比 Pt-GG (1.7%) 更能抑制 DNA 复制，并引起更多突变 (29.1%)。大多数突变是 Pt-GTG 交联中 5' G 残基处的 G 碱基变为 A 或 T 碱基变化。这些结果表明Pt-GTG交联成为癌细胞分裂的有效障碍，并且对于顺铂癌症治疗具有重要作用。 (C) 2014 Elsevier B.V. 保留所有权利。
Cisplatin (cis-diamminedichloroplatinum(II)), a widely used anticancer drug, forms inter- and intra-strand DNA crosslinks. The major intra-strand crosslinks are Pt adducts at 1,2-d(GpG) and 1,3-d(GpNpG) (Pt-GG and Pt-GNG, respectively). Although most of the intra-strand crosslinks are removed by the nucleotide excision repair (NER), the remaining crosslinks can cause mutations through the translesion DNA synthesis (TLS) during chromosome replication. To understand the precise mechanism of cisplatin mutagenesis in human cells, the plasmid carrying a single Pt-GG or 1,3-d(GpTpG) crosslink (Pt-GTG) site-specifically in lacZ gene was constructed and propagated in NER-defective xeroderma pigmentosum cells. The plasmids retrieved from the cells were introduced into indicator bacterial cells to access frequencies of TLS and mutations. The experiments revealed that Pt-GTG blocked DNA replication more strongly and caused more mutations (29.1%) than Pt-GG (1.7%). Most mutations were G to A or T base changes at 5' G residue in the Pt-GTG crosslinks. These results indicate that the Pt-GTG crosslinks become effective obstacles for cancer cell division, and have an important role for cisplatin cancer therapy. (C) 2014 Elsevier B.V. All rights reserved.