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

基本信息

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
项目类别：
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

项目摘要

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.

通过烷基化诱变剂和致癌物对 DNA 进行共价修饰与癌症密切相关已知多种烷化剂可攻击 DNA 产生 N7-烷基鸟嘌呤 (N7-)。尽管在这方面取得了重大进展，但烷基G）和烷基甲酰胺嘧啶（烷基-FapyG）损伤。病变的化学、生化和/或诱变特性的表征，我们的分子水平了解致癌物/药物诱导的大体积插入 N7-烷基G 的结构和生物效应除了黄曲霉毒素B1-N7G加合物等少数病变外，烷基-FapyG加合物仍然有限。知识差距部分是由于产生足够数量 DNA 的技术限制造成的含有位点特异性掺入的 N7-烷基G；尽管双链 DNA 中的 N7-烷基G 损伤的半衰期为几个小时到几天，核苷的损伤在化学上极其不稳定，会迅速发生自发脱嘌呤，从而排除了使用固相法合成 N7- 我们之前开发了一种过渡态不稳定策略来解决这个问题。化学不稳定性问题，并报道了第一个含 N7-烷基 G 的 DNA 晶体结构。拟议研究的中心假设是庞大的、可插入的 N7-烷基G 和烷基-FapyG 病变影响 DNA 结构和生物过程，包括 DNA 复制和突变。研究目标是阐明致癌物/药物诱导的 N7-烷基G 和 N7-烷基G 的结构和生物效应 N3-烷基腺嘌呤损伤的目的是阐明 N7-烷基G 和烷基-FapyG 的影响。 DNA结构、复制和突变的损伤，并剖析DNA修复机制为了实现这一目标，我们提出了合成、结构测定和生化。评估由强效致癌物/药物（包括 N-）引起的 N7-烷基G 和烷基-FapyG 病变甲基苄基亚硝胺、黄樟素、ptaquiloside、吖啶半芥子ICR-191、氮半芥子和作为实现我们长期目标的下一步，我们设计了基于铂的“类烷基化”剂。三个具体目标是 1) 评估 N7-烷基G 和烷基-FapyG 损伤对双链 DNA 的结构和稳定性；2) 阐明病变的诱变机制；3) 描绘损伤的 DNA 修复机制是我们的期望。拟议的研究将促进我们对可插入 N7-烷基G 的影响的分子水平理解和烷基-FapyG 加合物对 DNA 结构、复制和突变以及 DNA 修复机制的影响病变，从而为烷基化诱导的突变和致癌的病因学提供新的见解。此外，含有 N7-烷基G 的 DNA 的晶体结构将有助于基于结构的设计和开发可以改变 DNA 结构和生物过程的新型烷化剂。