Using Adductomics to Characterize Exposures to Carcinogens

 描述（由申请人提供）：尽管流行病学证据表明大多数人类癌症是由未知的致癌物暴露引起的，但流行病学家仍然依赖自我报告的信息来描述暴露，就像他们在世纪前所做的那样。为了提供高质量的数据，从不同的外源性和内源性来源的致癌物暴露，癌症病因学的研究应该使用血液中的化学物质的非靶向组学。不幸的是，许多致癌物不能在血液中测量，因为它们是活性亲电体，在体内寿命短。评估这些有意义的暴露的途径集中在反应性亲电试剂和血液蛋白之间反应的加合物上。人血清白蛋白（HSA）中的加合物特别有吸引力，因为HSA是血清中最丰富的蛋白质，Cys34是血清中反应性亲电体的主要清除剂。HSA的其他亲核热点包括Lys199和His146。虽然一些HSA加合物的水平与暴露于目标化学品有关，但大量未表征的加合物代表了未知的暴露，无疑有助于癌症的发病率。因此，"HSA加合物"，代表了所有这些加合物，是癌症流行病学的巨大潜在的重要性。由于所有反应性亲电体都是可能的致癌物，因此HSA内收体的测量可以说比蛋白质组或代谢组更相关于人类癌症引发剂的发现，蛋白质组或代谢组两者都被应用于研究癌症病因。 在先前的NIH资助下，我们使用三重四极杆质谱法（MS）对Cys34加合物与人血清样品进行非靶向分析。尽管该项目提供了概念验证，但覆盖范围仅限于Cys34修饰，三重四极杆MS无法提供用于注释的准确质量。我们最近表明，液相色谱-高分辨率质谱法更适合于内收体，并开发了一个强大的'内收体管道'表征Cys34加合物。拟议项目的目标是通过同时测量Cys34，Lys199和His146的加合物来扩大HSA内收体的覆盖范围。在改进技术后，我们将用健康成人的血浆标本验证方法，并将用来自EPIC-意大利前瞻性队列研究的非霍奇金淋巴瘤（NHL）事件病例和匹配对照的存档血清对癌症流行病学技术进行初步测试。这项技术的成功创新可以改变发现人类癌症起源的方法。

 DESCRIPTION (provided by applicant): Although epidemiologic evidence indicates that most human cancers are caused by unknown exposures to carcinogens, epidemiologists still rely on self-reported information to characterize exposures, much as they did a century ago. To provide high-quality data regarding carcinogen exposures from diverse exogenous and endogenous sources, studies of cancer etiology should use untargeted omics of chemicals in blood. Unfortunately, many carcinogens cannot be measured in blood because they are reactive electrophiles with short life spans in vivo. An avenue for assessing these meaningful exposures focuses on adducts from reactions between reactive electrophiles and blood proteins. Adducts in human serum albumin (HSA) are particularly appealing because HSA is the most abundant protein in serum and Cys34 is the dominant scavenger of reactive electrophiles in serum. Other nucleophilic hotspots of HSA include Lys199 and His146. Although levels of some HSA adducts have been correlated with exposures to targeted chemicals, a plethora of uncharacterized adducts represent unknown exposures that undoubtedly contribute to cancer incidence. Thus the `HSA adductome', representing the totality of such adducts, is of great potential importance to cancer epidemiology. Since all reactive electrophiles are possible carcinogens, measurement of the HSA adductome is arguably more relevant to the discovery of initiators of human cancers than the proteome or the metabolome, both of which are being applied to investigate cancer causation. With previous NIH funding, we used triple-quadrupole mass spectrometry (MS) to perform untargeted analyses of Cys34 adducts with samples of human serum. Although that project provided proof-of-concept, coverage was limited to Cys34 modifications and triple-quadrupole MS did not provide accurate masses for annotation. We recently showed that liquid chromatography-high resolution mass spectrometry was more appropriate for adductomics and developed a robust `adductomics pipeline' for characterizing Cys34 adducts. The goals of the proposed project are to expand coverage of HSA adductomics by simultaneously measuring adducts of Cys34, Lys199 and His146. After improving the technology, we will validate methods with specimens of plasma from healthy adults and will pilot-test the technology for cancer epidemiology with archived serum from incident cases of non-Hodgkin's lymphoma (NHL) and matched controls from the EPIC- Italy prospective cohort study. Successful innovations of this technology can transform approaches to discover the origins of human cancers.