INFLUE HETEROCYCLIC AMINE METABOLIC POLYMORPH ON BIOACTIVAT PHIP IN HUMAN COLON

影响人结肠中生物活性剂 PHIP 的杂环胺代谢多晶型

• 批准号: 7602403
• 负责人: NICHOLAS PAUL LANG
• 金额: $ 2.1万
• 依托单位: UNIVERSITY OF CALIF-LAWRNC LVRMR NAT LAB
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-01 至 2008-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7602403
• 关键词: 2-Amino-1-Methyl-6-Phenylimidazo[4,5-b]pyridine; Area; CYP1A2 gene; Cancer Etiology; Carcinogens; Colon; Colon Carcinoma; Colonic Neoplasms; Computer Retrieval of Information on Scientific Projects Database; DNA Adduction; DNA Adducts; DNA analysis; Data; Data Analyses; Data Set; Development; Diagnosis; Diet; Disease; Dose; Environmental Exposure; Enzymes; Etiology; Exposure to; Funding; GSTM1 gene; Genotype; Genus Cola; Glucuronides; Grant; Heterocyclic Amines; Human; Human Volunteers; Individual; Institution; Investigation; Knowledge; Label; Laboratory Animals; Malignant Neoplasms; Malignant neoplasm of lung; Malignant neoplasm of prostate; Meat; Metabolic; Metabolism; NAT2 gene; Operative Surgical Procedures; Outcome; Pathway interactions; Phenotype; Pilot Projects; Play; Predisposition; Prevention strategy; Radioactive; Research; Research Personnel; Resources; Risk Factors; Rodent; Role; Sampling; Schedule; Source; Statistically Significant; Thinking; Tissues; United States National Institutes of Health; Urine; Variant; Work; accelerator mass spectrometry; adduct; base; cooking; enzyme activity; glucuronide; glutathione S-transferase M1; human subject; malignant breast neoplasm; neutrophil; tumor; urinary; volunteer

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The main objective of this research is to confirm the role of PhIP metabolism in colon cancer by demonstrating that the NAT2 and CYPIA2 phenotype, as well as GSTM1 and CYPIA1 genotype are related to the level of PhIP-DNA adducts formed in humans administered dietary relevant levels of 14C-PhIP. These factors are important to study because they represent enzymes that are thought to be important in PhIP metabolism based on rodent studies. The outcome of this work will be additional proof that heterocyclic amines such as PhIP are involved in colon cancer since these enzymes are active in the metabolism of heterocyclic amines. Additionally, this work will show whether genotype or phenotype are potentially useful markers of PhIP susceptibility for colon cancer. We have collected data in humans to establish the role of PhIP metabolism in colon cancer by determining the relationship between NAT2 and CYPIA2 phenotype, as well as GSTM1 and CYPIA1 genotype and the level of PhIP-DNA adducts formed in humans. This was accomplished by administering very low levels of 14C-labeled PhIP to human subjects with a diagnosis of colon cancer who are scheduled for surgery. Data so far from 10 subjects indicates that SULT, NAT2 and CYP1A2 phenotypes influence adduct levels in the colon. A larger, more statistically significant, study is planned to verify the findings. There is a need to perform similar work in other cancers such as breast cancer, prostate cancer and lung cancer. In each of these areas, the disease toll is great, the prevention strategies are limited by a knowledge deficit in the areas of disease etiology and metabolism pathway and exposure information is incomplete. Study summary and results: One of the most significant sources of environmental exposures to carcinogens is through the diet. Epidemiologic evidence indicates that exposure to heterocyclic amines (HAs) in the diet is an important risk factor for the development of colon cancer. Well-done cooked meats contain significant levels of HAs which have been shown to cause cancer in laboratory animals. To better understand the mechanisms of HA bioactivation and potential tumor induction in humans, the most mass abundant HA, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), was used to assess the relationship between PhIP metabolism and DNA adduct formation. Ten human volunteers where administered a dietary relevant dose of 14C-PhIP (70-84 ¿g) 48-72 h prior to surgery to remove colon tumors. Urine was collected for 24 h after dosing for metabolite analysis, and DNA was extracted from colon tissue and analyzed by accelerator mass spectrometry for DNA adducts. All ten subjects were also phenotyped for CYP1A2, NAT2, and SULT1A1 enzyme activity. Twelve radioactive peaks associated with PhIP were detected in the urine samples. The most abundant metabolite in all ten volunteers was identified as N-hydroxy-PhIP-N2-glucuronide. Variation in the levels of metabolites between volunteers was observed. Colon DNA adducts were detected in all ten volunteers. Interindividual differences were evident in the levels of DNA adducts between each individual. Analysis of the data showed that individuals with high levels of urinary N-hydroxy-PhIP-N2-glucuronide, and that were categorized as having a rapid CYP1A2 phenotype had the lowest level of colon PhIP-DNA adducts. Significance: These data suggest that glucuronidation plays a significant role in detoxifying N-hydroxy-PhIP. Statistical analyses showed that levels of urinary N-hydroxy-PhIP-N2-glucuronide were negatively correlated to colon DNA adduct levels. Although it is difficult to make definite conclusions from a small data set, the results from this pilot study have encouraged further investigations using a much larger study group.

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 本研究的主要目的是通过证明NAT 2和CYPIA 2表型以及GSTM 1和CYPIA 1基因型与给予饮食相关水平14 C-PhIP的人体中形成的PhIP-DNA加合物水平相关，确认PhIP代谢在结肠癌中的作用。 这些因素对于研究很重要，因为它们代表了基于啮齿动物研究被认为在PhIP代谢中很重要的酶。 这项工作的结果将进一步证明杂环胺如PhIP参与结肠癌，因为这些酶在杂环胺的代谢中具有活性。 此外，这项工作将显示基因型或表型是否是结肠癌PhIP易感性的潜在有用标记。 我们收集了人体数据，通过确定NAT 2和CYPIA 2表型之间的关系，以及GSTM 1和CYPIA 1基因型和人体中形成的PhIP-DNA加合物水平，确定PhIP代谢在结肠癌中的作用。 这是通过给予非常低水平的14 C-标记的PhIP与结肠癌的诊断谁是预定手术的人类受试者来实现的。迄今为止，来自10名受试者的数据表明，SULT、NAT 2和CYP 1A 2表型影响结肠中的加合物水平。计划进行一项更大规模、更具统计学意义的研究，以验证这些发现。 有必要在其他癌症如乳腺癌、前列腺癌和肺癌中进行类似的工作。 在这些地区中，疾病造成的死亡人数都很高，预防战略受到疾病病因学和代谢途径方面知识不足的限制，而且接触信息不完整。 研究总结和结果： 环境暴露于致癌物质的最重要来源之一是通过饮食。 流行病学证据表明，暴露于饮食中的杂环胺（HAs）是结肠癌发生的重要危险因素。 熟透的熟肉含有大量的HA，这些HA已被证明会导致实验室动物的癌症。 为了更好地理解人类中HA生物活化和潜在肿瘤诱导的机制，使用质量丰度最大的HA 2-氨基-1-甲基-6-苯基咪唑[4，5-B]吡啶（PhIP）来评估PhIP代谢与DNA加合物形成之间的关系。 在手术切除结肠肿瘤前48-72小时，对10名志愿者给予饮食相关剂量的14 C-PhIP（70-84 μ g）。 给药后24小时收集尿液用于代谢物分析，从结肠组织中提取DNA，并通过加速器质谱法分析DNA加合物。 所有10例受试者还进行了CYP 1A 2、NAT 2和SULT 1A 1酶活性的表型分析。 在尿样中检测到12个与PhIP相关的放射性峰。 在所有10名志愿者中，最丰富的代谢产物被鉴定为N-羟基-PhIP-N2-葡糖苷酸。 观察到志愿者之间代谢物水平的变化。 在所有10名志愿者中检测到结肠DNA加合物。 个体间差异是明显的，在每个人之间的DNA加合物的水平。 数据分析显示，尿N-羟基-PhIP-N2-葡萄糖醛酸苷水平高且归类为快速CYP 1A 2表型的个体的结肠PhIP-DNA加合物水平最低。 意义：这些数据表明，葡萄糖醛酸化在解毒N-羟基-PhIP中起着重要作用。 统计分析显示，尿N-羟基-PhIP-N2-葡萄糖醛酸苷水平与结肠DNA加合物水平呈负相关。 虽然很难从一个小的数据集得出明确的结论，但这项试点研究的结果鼓励了使用更大的研究小组进行进一步的研究。