PROTEIN ADDUCTS AS MOLECULAR SIGNATURES OF CARCINOGEN DOSE

由于接触致癌物的来源和途径很多，流行病学研究应该 使用内剂量的生物标志物作为致癌物质暴露的替代品。然而，直接测量 致癌物质是不切实际的，因为这些化学物质通常是寿命短的活性亲电物质。 身体。作为替代方案，可通过添加产物(加合物)研究致癌剂量 与血液蛋白质，特别是人血清白蛋白(HSA)和血红蛋白(Hb)的亲电性。因为 这些加合物没有修复，它们反映了一到两个月内致癌物质的剂量。在这个项目中，我们 设想一个‘蛋白质加合物组’，代表存在于给定蛋白质上的所有加合物，作为一个实体 毒理基因组学重要性。由于所有的亲电物种都具有潜在的致癌作用，所以蛋白质加合物 可以说，与蛋白质组或代谢组相比，与致癌物质的发现更相关。 尽管它们可用作致癌剂量的生物标记物，但血液中含有大量有毒化学物质的加合物 蛋白质，如人血清白蛋白(HSA)和Hb，很少用于流行病学研究或用于 发现人类癌症的始作俑者。造成这种情况的主要原因有三个。第一，没有实质性的 加合物浓缩，HSA和Hb加合物的典型浓度太低，不允许广泛* 新致癌物质的发现。这是大海捞针的问题，也困扰着蛋白质组学。 调查。其次，最先进的质谱学(MS)还没有被用来识别未知的 蛋白质加合物或分析与人类癌症有关的加合物。第三，取血难。 用来测定蛋白质加合物的样品。 在这个项目中，我们假设特定的亚加成体，如人血清白蛋白的游离半胱氨酸(Cys34)， 可用于发现新的致癌物，并在大规模流行病学中作为内剂量的生物标志物 学习。为了考虑这些问题，我们将选择性地从人血中富集人血清白蛋白的半胱氨基加合物。 然后用MS对已知和未知的HSA加合物进行表征。通过比较加和图 在淋巴瘤病例和对照受试者之间，我们将确定可能的致癌物。关于使用 在流行病学研究中的蛋白质加合物，我们将与项目3合作确定其是否可行 为了快速测定一滴血中多环芳烃(PAH)的蛋白质加合物。

Because exposures to carcinogens arise from many sources and routes, epidemiology studies should use biomarkers of internal dose as surrogates for carcinogen exposures. However, direct measurement of carcinogens is impractical because these chemicals are usually reactive electrophiles with short life spans in the body. As an alternative, carcinogen doses can be investigated via addition products (adducts) of the electrophiles with blood proteins, especially human serum albumin (HSA) and hemoglobin (Hb). Because these adducts are not repaired, they reflect doses of carcinogens over one to two months. In this project, we envision a 'protein adductome', representing all adducts present on a given protein, as an entity of toxicogenomic importance. Since all electrophilic species are potentially carcinogenic, the protein adductome is arguably more relevant to carcinogen discovery than the proteome or the metabolome. Despite their utility as biomarkers of carcinogen dose, adducts of toxic chemicals with abundant blood proteins, such as human serum albumin (HSA) and Hb, have rarely been used in epidemiology studies or to discover the initiators of human cancers. There are three major reasons for this. First, without substantial adduct enrichment, typical concentrations of HSA and Hb adducts are too low to permit widespread * discovery of new carcinogens. This is the 'needle-in-a-haystack problem' that has also plagued proteomic investigations. Second, state-of-the-art mass spectrometry (MS) has not been exploited to identify unknown protein adducts or to profile adducts with links to human cancers. And third, it is difficult to obtain blood samples with which to assay protein adducts. In this project, we hypothesize that particular subadductomes, such as the free cysteine of HSA (Cys34), can be used to discover new carcinogens and to serve as biomarkers of internal dose in large epidemiology studies. To consider these questions, we will selectively enrich cysteinyl adducts of HSA from human blood and then will use MS to characterize the known and unknown HSA adducts. By comparing adduct maps between lymphoma cases and control subjects, we will pinpoint possible carcinogens. Regarding the use of protein adducts in epidemiology studies, we will collaborate with Project 3 to determine whether it is feasible to quickly measure protein adducts of polycyclic aromatic hydrocarbons (PAH) in a single drop of blood.