Repair and Biological Consequences of Alkylated Thymidine Lesions

 描述（由申请人提供）：环境暴露和内源性代谢均引起DNA烷基化，DNA烷基化代表了许多常用癌症化疗药物的主要作用机制。因此，评估烷基化DNA损伤如何通过改变DNA复制和转录的效率和保真度来损害遗传信息的流动，以及这些损伤如何影响DNA复制和转录。 修复将为理解DNA烷基化在人类疾病发生的病因学中的意义提供重要的知识。这些知识也将成为制定更好的癌症化疗策略的基础。本申请的重点是一组烷基化胸苷损伤，这些损伤已显示在哺乳动物组织中持续存在或在暴露于香烟烟雾的人的淋巴细胞样品中检测到显著升高的水平。我们将采用创新和多管齐下的方法，包括合成有机化学，基于质谱的生物分析化学和分子生物学，以实现分子水平的了解，了解未充分研究的烷基化胸苷损伤如何阻碍细胞中的DNA复制和转录，并在这些过程中诱导突变。我们还将评估核苷酸切除修复和碱基切除修复途径在修复细胞中这些病变的影响。拟议研究的结果将使我们对这一被严重忽视的烷基化DNA损伤组的理解达到更高的水平。

 DESCRIPTION (provided by applicant): Environmental exposure and endogenous metabolism both give rise to the alkylation of DNA, and DNA alkylation represents the major mechanism of action for a number of commonly prescribed cancer chemotherapeutic agents. Thus, assessing how alkylated DNA lesions compromise the flow of genetic information by altering the efficiency and fidelity of DNA replication and transcription and how these lesions are repaired will provide important knowledge for understanding the implications of DNA alkylation in the etiology for developing human diseases. Such knowledge will also form the basis for developing better strategies for cancer chemotherapy. The emphasis of this application is placed on a group of alkylated thymidine lesions which have been shown to persist in mammalian tissues or have been detected at substantially elevated levels in lymphocyte samples of humans exposed to cigarette smoke. We will employ an innovative and multi- pronged approach, including synthetic organic chemistry, mass spectrometry-based bioanalytical chemistry, and molecular biology to achieve a molecular-level understanding about how the under-investigated group of alkylated thymidine lesions impede DNA replication and transcription in cells, and induce mutations in these processes. We will also assess the implications of nucleotide excision repair and base excision repair pathways in the repair of these lesions in cells. The outcome of the proposed research will bring our understanding of this largely overlooked group of alkylated DNA lesions to a significantly higher level.