Synthesis, structure and biological effects of carcinogen/drug-induced bulky, intercalatable N7-alkylguanine lesions

致癌物/药物引起的大块插入式N7-烷基鸟嘌呤损伤的合成、结构和生物学效应

• 批准号: 9754147
• 负责人: Seongmin Lee
• 金额: $ 27.62万
• 依托单位: UNIVERSITY OF TEXAS AT AUSTIN
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2022-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9754147
• 关键词: Acridines; Affect; Aflatoxin B1; Alkylating Agents; Alkylation; Base Pairing; Biochemical; Biological; Biological Assay; Biological Models; Biological Process; Carcinogens; Chemicals; Cisplatin; Complex; Crystallization; DNA; DNA Adducts; DNA Maintenance; DNA Modification Process; DNA Repair; DNA Structure; DNA biosynthesis; DNA-Directed DNA Polymerase; Depurination; Development; Escherichia coli; Ethylenes; Etiology; Evaluation; Excision; Genetic Transcription; Goals; Guanine; Heterogeneity; Hour; In Vitro; Knowledge; Lesion; Malignant Neoplasms; Mechlorethamine; Mediating; Methods; Molecular; Molecular Conformation; Mustard; Mutagenesis; Mutagens; NMR Spectroscopy; Nitrogen; Nitrosamines; Nucleosides; Nucleotide Excision Repair; Oligonucleotides; Pharmaceutical Preparations; Phase; Platinum; Property; Proteins; Public Health; Quinones; Reporting; Research; Retrieval; Role; Safrole; Site; Solid; Structure; System; Testing; Thermodynamics; Thymine; Tobacco; adduct; antitumor agent; base; cancer cell; carcinogenesis; crosslink; design; erythritol anhydride; expectation; in vivo; insight; intercalation; ionization; leinamycin; novel; polymerization; programs; repaired; styrene oxide; three dimensional structure

Covalent modification of DNA by alkylating mutagens and carcinogens is closely associated with cancer development. A wide variety of alkylating agents are known to attack DNA to produce N7-alkylguanine (N7- alkylG) and alkyl formamidopyrimidine (alkyl-FapyG) lesions. Despite the major advances in the characterization of chemical, biochemical, and/or mutagenic properties of the lesions, our molecular-level understanding of structural and biological effects of carcinogen/drug-induced bulky intercalatable N7-alkylG and alkyl-FapyG adducts is still limited, except for a few lesions such as aflatoxin B1-N7G adducts. This knowledge gap had been due in part to a technical limitation in generating sufficient quantities of DNA containing site-specific incorporated N7-alkylG; although N7-alkylG lesions in duplex DNA have half-lives of several hours to days, the lesions in nucleosides are chemically extremely unstable to rapidly undergo spontaneous depurination, thereby precluding the use of the solid-phase method for the synthesis of N7- alkylG-containing DNA. We previously developed a transition-state destabilization strategy to solve the chemical instability problem and reported the first crystal structure of an N7-alkylG-containing DNA. Our central hypothesis of the proposed research is that bulky, intercalatable N7-alkylG and alkyl-FapyG lesions affect DNA structure and biological processes including DNA replication and mutagenesis. Our long-term research goal is to elucidate the structural and biological effects of carcinogen/drug-induced N7-alkylG and N3-alkyladenine lesions. The objectives here are to elucidate the impacts of N7-alkylG and alkyl-FapyG lesions on DNA structure, replication and mutagenesis and to dissect the DNA repair mechanism of the lesions. To accomplish this objective, we propose synthesis, structure determination, and biochemical evaluation of N7-alkylG and alkyl-FapyG lesions that are induced by potent carcinogens/drugs including N- methylbenzyl nitrosamine, safrole, ptaquiloside, acridine half-mustard ICR-191, nitrogen half-mustard, and a platinum-based “alkylating-like” agent. As a next step for achieving our long-term goals, we have designed three Specific Aims that are 1) Evaluating the impact of the N7-alkylG and alkyl-FapyG lesions on the structure and stability of duplex DNA; 2) Elucidating the mutagenesis mechanisms of the lesions; and 3) Delineating the DNA repair mechanism for the lesions. Our expectation is that the accomplishment of the proposed research would advance our molecular-level understanding of the impact of intercalatable N7-alkylG and alkyl-FapyG adducts on DNA structure, replication and mutagenesis and the repair mechanism of the lesions, thereby providing new insights into the etiology of alkylation-induced mutagenesis and carcinogenesis. In addition, crystal structures of N7-alkylG-containing DNA would facilitate a structure-based design and development of novel alkylating agents that can alter DNA structure and biological processes.

通过烷基化突变和致癌物对DNA的共价修饰与癌症密切相关 发展。已知多种烷基化剂会攻击DNA产生N7-烷基鸟嘌呤（N7-- 烷基）和烷基甲酰胺嘧啶（烷基 - 酸性）病变。尽管在 病变的化学，生化和/或诱变特性的表征，我们的分子级 了解致癌/药物诱导的笨重室内可盐N7-烷基的结构和生物学作用 除了一些病变，例如黄曲霉毒素B1-N7G加合物之外，烷基 - 饮食加合物仍然有限。这 知识差距部分归因于产生足够数量的DNA的技术限制 包含特定于位点的N7-Alkylg；尽管双链DNA中的N7-烷基病变具有半衰期 几个小时到几天，核外侧的病变在化学上非常不稳定，以迅速发生 赞助部署，从而排除使用固相法进行N7-的合成 含烷基的DNA。我们以前制定了一种过渡状态的不稳定策略，以解决 化学不稳定性问题，并报道了含N7-烷基的DNA的第一个晶体结构。我们的 拟议的研究的中心假设是笨重，可溶解的N7-烷基和烷基 - 酸性病变 影响DNA结构和生物过程，包括DNA复制和诱变。我们的长期 研究目标是阐明致癌物/药物诱导的N7-烷基的结构和生物学作用 N3-烷基腺苷病变。这里的目的是阐明N7-烷基和烷基-FAPYG的影响 关于DNA结构，复制和诱变的病变，并剖析DNA修复机制 病变。为了实现这一目标，我们提出合成，结构确定和生化 评估有效的致癌物/药物（包括N- 甲基苯甲酰硝基胺，safrole，ptaquiloside，acridine Half-mustard ICR-191，氮半粘剂和A 基于铂类的“烷基化”剂。作为实现长期目标的下一步，我们设计了 1）评估N7-烷基和烷基 - 酸性病变对该影响的三个具体目的 双链DNA的结构和稳定性； 2）阐明病变的诱变机制； 3） 描述病变的DNA修复机制。我们的期望是成就 拟议的研究将提高我们对可估量N7-烷基影响的分子水平的理解 和烷基 - 饮食加合物在DNA结构，复制和诱变以及修复机制上 病变，从而提供了有关酗酒诱导的诱变和致癌作用的病因的新见解。 另外，含N7-烷基DNA的晶体结构将促进基于结构的设计和 可以改变DNA结构和生物过程的新型烷基化剂的开发。