DNA ADDUCTS OF DIET CARCINOGENESIS--ANALYSIS BY 32P & MS

污染物/致癌物暴露的分子标志物越来越多地被用于 毒理学家和流行病学家评估人类健康的重要工具 健康风险。 最直接的证据表明，最近的接触和遗传 损伤是通过测量细胞中的DNA致癌物加合物。 的 该计划的长期目标是提高我们对 某些饮食产生的DNA加合物与肿瘤发生之间的关系。 杂环芳香胺（HAA），一类强致癌物， 在肉类和鱼类的烹饪过程中，是本研究的重点。 流行病学研究表明， HAA会增加结肠直肠癌和胰腺癌的风险。 的DNA 三种特定的杂环芳香胺的加合物，2-氨基-1-甲基- 6-苯基咪唑并[4，5 b]吡啶（PhIP），2-氨基-3-甲基咪唑并[4，5-f] 喹啉（IQ）和2-氨基-3，8-二甲基咪唑并[4，5-f]喹喔啉（MeIQx）， 它与多种致癌功能有关， 小鼠淋巴瘤、大鼠结肠癌和非人肝癌 灵长类动物，是检查的目标。 改进的检测方法 对它们的DNA加合物进行鉴定是重要的第一步 实现这一目标，并在计划中强调。 动物模型与人类有种间相似性， 作为替代品，以开发生物标志物来评估人类健康 风险由HAA。 还将检查体外反应， 更大量的参比加合物。 毛细管分离法 （液相色谱法或毛细管区带电泳法） 电喷雾电离（ESI）/串联质谱，其允许 将使用完整DNA加合物分析和32/P后标记， 平行比较以表征肝脏的HAA-DNA加合物含量 组织中 毛细管LC-（或CZE）-MS/MS的高信息量 分析方法将补充高灵敏度/低灵敏度 32/P后标记结构信息含量法。 MS数据 因此，将作为32/P方法的评价和验证， 随后适用于人体样本的检验， 暴露水平明显较低。 预计该 从拟议的研究中产生的信息将提供新的见解， 使用生物标志物进行风险评估和饮食调整， 来降低饮食致癌的风险

Molecular markers of contaminant/carcinogen exposure are an increasingly important tool for toxicologists and epidemiologists in assessing human health risk. The most direct evidence of recent exposure and genetic damage is through the measurement of DNA carcinogen adducts in cells. The long-term objective of this program is to improve our understanding of the relationship between certain diet-generated DNA adducts and tumorigenesis. Heterocyclic aromatic amines (HAA's), a class of potent carcinogens formed during the cooking of meat and fish, are the focus of this study. Epidemiological studies suggest that the consumption of foods that contain HAA's increases the risk to colorectal and pancreatic cancer. The DNA adducts of three specific heterocyclic aromatic amines, 2-amino-1-methyl- 6-phenylimidazo[4,5b]pyridine (PhIP), 2-amino-3-methylimidazo[4,5-f] quinoline (IQ) and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), which are associated with a variety of carcinogenic functions including lymphomas in mice, colon cancer in rats and liver cancer in non-human primates, are targeted for examination. Improved methods for detection and characterization of their DNA adducts is an important first step toward accomplishing this goal and is emphasized in the program. Animal models, which have interspecies similarities to humans, will be used as surrogates in order to develop biomarkers to assess human health risk due to HAA's. In vitro reactions will also be examined to provide larger quantities of reference adducts. Capillary separation methods (liquid chromatography or capillary zone electrophoresis) coupled to electrospray ionization (ESI)/tandem mass spectrometry, which permits the analysis of intact DNA adducts, and 32/P post-labelling will be used and compared in parallel to characterize the HAA-DNA adduct content of liver tissues. The high information content of the capillary LC-(or CZE)-MS/MS method of analysis will complement that of the high sensitivity/low structural information content method of 32/P post-labelling. The MS data will thus serve as evaluation and validation of the 32/P method for its subsequent application to the examination of human specimens where the exposure levels are significantly lower. It is expected that the information generated from the proposed study will provide new insights on the use of biomarkers for risk assessment and diet modifications in order to minimize risk to dietary cancer.