New biomonitoring methodologies to measure DNA adducts in human tissues

描述（由申请人提供）：本提案的目的是开发新的生物监测方法，旨在测量暴露于化学致癌物的人体组织中的DNA加合物。我们这个项目的化学模型是结构相关的硝基菲羧酸，一类人类致癌物和肾毒物，包括马兜铃酸（AA）。这些化合物普遍存在于马兜铃属的草药中，在世界各地用于药用目的已有2000年。含有AA的草药的肾毒性和致癌性有很好的记录。流行病学研究表明，AA是被称为中国草药和巴尔干半岛的地方性肾病的临床综合征的致病因子。在后者中，暴露于AA涉及摄入由马兜铃属clematitis种子污染的面粉制成的面包。由于其毒性，含有AA的传统中草药在一些国家被禁止进口，但不是所有国家。尽管食品和药物管理局对含有AA的植物药的安全性发出警告，但这些草药仍然通过互联网在美国广泛分布，并且由于暴露于AA而导致的慢性肾衰竭和尿路上皮癌的发病率在全球范围内仍然非常高。 最近，我们提供了明确的证据AA-DNA加合物的存在下，在肾皮质的患者受BEN，使用一种新的，多级离子阱质谱（MSn）方法。定量MS方法是必不可少的测量DNA加合物的生物标志物，这种毁灭性的和均匀的致命疾病。生物监测方法将用于在居民饮食暴露于AA的巴尔干半岛的国家进行的转化研究。通过将AA-DNA加合物的分析从新鲜冷冻的组织样本扩展到存档的福尔马林固定的肾组织，将实现DNA加合物筛选方法的关键技术进步，这是一种尚未开发但丰富的毒理学研究材料来源。最后，将建立一种新的筛选方法，采用自动芯片为基础的输液纳米电喷雾串联MS方法。该技术将为基于人群的研究中筛选DNA加合物提供一种快速通量和成本效益高的方法。 含有致癌AA的传统草药在世界范围内使用，是一个全球性的健康问题。最近的流行病学研究表明，含有AA的草药与肾衰竭和癌症有关。需要快速和定量分析MS数据来筛选AA-DNA加合物，以评估AA在肾病和上尿路上皮癌风险中的暴露和因果作用。AA-DNA加合物也是研究巴尔干半岛的地方性肾病及其相关上尿路上皮癌遗传易感性的关键生物标志物。本申请中建立的新型生物监测技术可应用于检查其他化学致癌物在人类癌症病因学中的作用。

DESCRIPTION (provided by applicant): The objective of this proposal is to develop new biomonitoring methodologies designed to measure DNA adducts in tissues of humans exposed to chemical carcinogens. Our chemical model for this project is structurally related nitro-phenanthrene carboxylic acids, a class of human carcinogens and nephrotoxicants that include aristolochic acids (AA). These compounds are universally present in herbs of the genus Aristolochia, used for medicinal purposes throughout the world for 2000 years. The nephrotoxicity and carcinogenicity of herbs containing AA are very well documented. Epidemiologic studies reveal AA to be the causal agent for the clinical syndromes known as Chinese herb and Balkan endemic nephropathies. In the latter, exposure to AA involves ingestion of bread prepared from flour contaminated with seeds of Aristolochia clematitis. Due to their toxicities, importation of traditional Chinese herbs containing AA are banned in some, but not all countries. Despite the Food and Drug Administration's warnings concerning the safety of botanical remedies containing AA, these herbs are still widely distributed in the United States via the Internet, and the incidence of chronic renal failure and urothelial cancer worldwide attributed to exposure to AA remains very high. Recently, we provided unequivocal evidence for the presence of AA-DNA adducts in the renal cortex of patients affected by BEN, using a novel, multi-stage ion trap mass spectrometry (MSn) method. Quantitative MS methods are essential for measuring DNA adduct biomarkers of this devastating and uniformally fatal disease. The biomonitoring methods will be used in translational research studies conducted in Balkan countries where the residents have dietary exposure to AA. A critical technological advance in DNA adduct screening methodologies will be achieved by extending the analysis of AA-DNA adducts from freshly frozen tissue samples to archived, formalin-fixed renal tissues, an untapped but rich source of material for toxico- logical research. Finally, a novel screening method will be established, employing an automated chip-based infusion nano-electrospray tandem MS method. This technique will provide a rapid throughput and cost- effective method to screen for DNA adducts in population-based studies. Traditional herbal remedies containing carcinogenic AA are used worldwide and are a global health problem. Recent epidemiological studies have linked herbs containing AA with renal failure and cancer. Rapid and quantitative analytical MS data to screen for AA-DNA adducts are needed to assess the exposure and the causal role of AA in nephropathy and upper urothelial cancer risk. The AA-DNA adducts also serve as critical biomarkers in studies of genetic susceptibility to Balkan endemic nephropathy and its associated upper urothelial cancer. The novel biomonitoring techniques established in this application can be appllied to examine the role of other chemical carcinogens in the etiology of human cancer.