Tang Yu, Chen Xiong, Wang Dongmei, Zhang Ruiping, Zhang Jinlan
State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China.
State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China.
Talanta. 2021 Jan 15;222:121500. doi: 10.1016/j.talanta.2020.121500. Epub 2020 Aug 10.
Alkylated DNA adducts are the most important and common form of DNA damage at the molecular level. In addition to known alkylated DNA adducts, many unknown DNA adducts remain to be discovered. A prediction-driven MRM profiling MS strategy has been established for the rapid discovery of unknown DNA adducts induced by sulfonates. The innovative aspects and core of this strategy are the construction of the prediction MRM list, which includes 36 possible precursor ion and characteristic product ion transitions of DNA adducts based on MS fragmentation patterns, and then unknown DNA adducts 7-propyl guanine and 7-butyl guanine were discovered based on the diagnostic MRM signals of the DNA samples, and subsequently confirmed using high-resolution MS data and synthetic standards for the first time. Furthermore, DNA adducts, including newly found adducts in a human cell model and rat tissues after nitrosamine and sulfonate exposure, were unambiguously investigated by a UHPLC-MS/MS method. As a result, different alkyl methanesulfonates, including methyl methanesulfonate (MMS), ethyl methanesulfonate (EMS), PMS and BMS, all lead to the formation of 7MeG in addition to their own specific alkylation DNA adducts. The ester group of the sulfonate determines the specific types of DNA adducts produced, and the sulfonate might undergo transesterification with the methyl donors that commonly exist in eukaryotic organisms such as SAM, resulting in the formation of MMS, which induce the generation of methyl DNA adducts after EMS, PMS and BMS exposure. Furthermore, similar DNA adduct profiles were presented in both human cells and rat tissues. This approach could be useful in the future for probing unknown DNA adducts and simultaneously profiling both known and unknown DNA adducts in both in vitro to in vivo settings to evaluate potential genotoxicities and cancer risks to populations exposed to genotoxins.
烷基化DNA加合物是分子水平上最重要且最常见的DNA损伤形式。除了已知的烷基化DNA加合物外，许多未知的DNA加合物仍有待发现。已建立了一种基于预测的MRM谱图质谱策略，用于快速发现由磺酸盐诱导的未知DNA加合物。该策略的创新点和核心是构建预测MRM列表，该列表基于质谱裂解模式包含36种可能的DNA加合物前体离子和特征产物离子跃迁，然后基于DNA样品的诊断MRM信号发现未知DNA加合物7-丙基鸟嘌呤和7-丁基鸟嘌呤，并首次使用高分辨率质谱数据和合成标准物进行了确认。此外，通过UHPLC-MS/MS方法对DNA加合物进行了明确研究，包括在亚硝胺和磺酸盐暴露后的人类细胞模型和大鼠组织中新发现的加合物。结果表明，不同的甲磺酸烷基酯，包括甲磺酸甲酯（MMS）、甲磺酸乙酯（EMS）、PMS和BMS，除了产生自身特定的烷基化DNA加合物外，均会导致7MeG的形成。磺酸盐的酯基决定了所产生的DNA加合物的特定类型，并且磺酸盐可能与真核生物中常见的甲基供体如SAM发生酯交换反应，从而形成MMS，在EMS、PMS和BMS暴露后诱导甲基DNA加合物的产生。此外，人类细胞和大鼠组织中呈现出相似的DNA加合物谱。这种方法未来可能有助于探测未知的DNA加合物，并同时在体外到体内环境中对已知和未知的DNA加合物进行谱图分析，以评估暴露于基因毒素的人群的潜在遗传毒性和癌症风险。
