DNA Repair of Endogenous Lesions in Carcinogenesis

癌变过程中内源性病变的 DNA 修复

• 批准号: 7800478
• 负责人: RABINDRA ROY
• 金额: $ 26.75万
• 依托单位: GEORGETOWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-26 至 2012-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7800478
• 关键词: 2-butenal; 4 hydroxynonenal; 8-hydroxyguanosine; Abbreviations; Acrolein; Address; Adenine; Age; Aldehydes; Animal Model; Animals; Base Excision Repairs; Biological Assay; Chronic; Chronic Hepatitis; Cinnamon - dietary; Copper; DNA; DNA Adducts; DNA Damage; DNA Repair; DNA glycosylase; Data; Development; Disease; Environmental Exposure; Enzymes; Excision; Genes; Goals; Hepatitis; Hepatocarcinogenesis; Hepatocyte; Hepatolenticular Degeneration; Human; Hydrogen Peroxide; Hydroxyl Radical; Inbred LEC Rats; Induced Mutation; Inflammation; Iron; Leg; Lesion; Life; Link; Lipids; Liver; Liver Extract; Long-Evans Rats; Luciferases; Lung; Malignant Neoplasms; Malignant neoplasm of liver; Malondialdehyde; Mammalian Cell; Mediating; Messenger RNA; Metabolism; Metals; Methylpurine DNA Glycosylase; Modeling; Molecular; Molecular Profiling; Mus; Mutation; Nucleotide Excision Repair; OGG1 gene; Organ; Oxidative Stress; Pathway interactions; Patients; Play; Primary carcinoma of the liver cells; Rat Strains; Rattus; Reactive Oxygen Species; Regulation; Reporter; Reporting; Research Personnel; Risk; Role; Staging; TP53 gene; Testing; Time; Tissue Extracts; Tissues; Tuberous Sclerosis; Tumor Promotion; Tumor Suppressor Genes; Uracil; Variant; adduct; age group; base; cancer prevention; cancer risk; carcinogenesis; dihydrouracil; endonuclease III; experience; genotoxicity; high risk; human APEX1 protein; mutant; nervous system disorder; oxidative DNA damage; oxidative damage; perhydroxyl radical; plasmid DNA; programs; promoter; repair enzyme; repaired; thymine glycol; tumor; tumorigenesis; uracil-DNA glycosylase

DESCRIPTION (provided by applicant): The broad long-term goal of this project is to elucidate the role of repair of endogenously modified DNA in the prevention of cancer. Our overall hypothesis is that the repair of endogenous DNA damage, including oxidized bases (Reactive Oxygen Species (ROS)-induced) and cyclic DNA adducts (enal-induced), plays a critical role in carcinogenesis. ROS and enals as such have been shown to elicit tumor promotion but detailed molecular mechanisms need to be elucidated. In this project we will use the Long Evans Cinnamon (LEG) rat as a model to investigate the mechanism. The LEG rat is genetically predisposed to spontaneous hepatocellular carcinoma (HCC). Like Wilson's disease (WD) patients, LEG rats accumulate excess copper in the liver and consequently the organ experiences severe inflammation and oxidative stress. As a result, the LEG rats develop hepatitis and the surviving animals get liver cancer. An important question is whether the chronic oxidative stress impairs repair capacity in LEG rats and as a consequence the increased oxidative damage and exocyclic adduct burden plays a critical role in HCC in LEG rat livers. Our preliminary results showed that DNA glycosylases (such as OGG1 and NTH1)-mediated excision activity of oxidized bases (8-oxoguanine and dihydrouracil) was significantly altered at different stages of HGG development in LEG rat compared to that in the control Long Evans Agouti (LEA) rat livers, and, thus prompted us to propose the following specific aims. These are to: (1) study activity and expression of repair DNA glycosylases and/or other enzymes, if found to be rate-limiting, in base excision repair (BER) pathway for repairing oxidized bases and etheno adducts in LEG and LEA rat livers, with lungs as a control; (2) study the mechanisms of regulation of NTH1 expression in LEG rat liver; (3) examine the mechanism of variation of expression and/or activity, if any, of DNA glycosylase(s) and/or other rate-limiting BER enzymes by assessing the effects of metals (copper and iron), hydrogen peroxide, and enals in hepatocytes of LEA and LEG rats and comparing the effects with that observed in tissues obtained from Aim 1; (4) study capacity to repair cyclic propano adducts (Acr-, Cro-, and HNE-dG) in LEG and LEA rat livers and lungs as control. Our preliminary results showed that HNE-dG, a major cyclic propano adduct is repaired by nucleotide excision repair (NER) pathway in mammalian cells including LEA and LEG livers. So, we will also examine the mechanism of variation, if found, of expression and/or activity of rate-limiting NER enzymes for repairing propano adducts by assessing the effects of enals in hepatocytes of LEA and LEG rats and comparing the effects with that observed in tissues. In summary, the data obtained by this project will be useful in elucidating the role of the endogenous DNA damage (oxidized bases and cyclic DNA adducts), and their repair in mutation and liver carcinogenesis.

描述（由申请人提供）：该项目的广泛长期目标是阐明内源性DNA在预防癌症中修复的作用。我们的总体假设是，内源性DNA损伤的修复，包括氧化的碱（活性氧（ROS）诱导的）和环状DNA加合物（依代诱导），在致癌作用中起着至关重要的作用。 ROS和趋势已显示出引起肿瘤的促进，但需要阐明详细的分子机制。在这个项目中，我们将使用长埃文斯肉桂（腿）大鼠作为研究机制的模型。腿大鼠在遗传上易于自发性肝细胞癌（HCC）。像威尔逊氏病（WD）患者一样，腿大鼠在肝脏中积累了多余的铜，因此器官会遭受严重的炎症和氧化应激。结果，腿大鼠患有肝炎，而幸存的动物患有肝癌。一个重要的问题是，慢性氧化应激是否会损害腿大鼠的修复能力，从而增加氧化损伤和外射合加合物负担在腿部大鼠肝脏中HCC中起着至关重要的作用。我们的初步结果表明，DNA糖基酶（例如OGG1和NTH1）介导的氧化碱基（8-氧甲烷和二羟氨核）的切除活性在腿部大鼠的HGG发育的不同阶段显着改变，与对照长的Evans Agouti（Lea）（Lea）agouti（Lea）（laine）的大鼠（laie）agouti（laie）的大鼠（laie agouti（Lea）（laine）的大鼠（laie）agouti（laie）的大鼠（laine）的大鼠（laine）的大鼠（laine）的大鼠（laine）较大（laie）的大鼠效应促进了我们的效力，并提出了以下质疑。这些是：（1）研究修复DNA糖基酶和/或其他酶的活性和表达，如果发现是限制速率的，则在基础切除修复（BER）修复途径（BER）途径中，用于修复腿部和LEA大鼠肝脏中的氧化碱基和Etheno加合物，并以肺为对照； （2）研究腿大鼠肝脏中NTH1表达调节的机制； （3）通过评估金属（铜和铁），过氧化氢）的影响（铜和铁）的影响，以及在果皮和腿大鼠的肝细胞中的影响，并在组织中观察到的效果，从而检查DNA糖基化酶（S）和/或其他限制速率的BER酶的表达和/或活性变化的机制（如果有）的机制（如果有）的机制。 （4）在腿部和LEA大鼠肝脏和肺中修复环状丙诺基合力（ACR-，Cro-和HNE-DG）的研究能力。我们的初步结果表明，HNE-DG是由哺乳动物细胞（包括LEA和腿部肝脏）中的核苷酸切除修复（NER）途径修复的主要环状加合物。因此，我们还将通过评估LEA和腿大鼠的肝细胞的影响，并将其与在组织中观察到的作用进行比较，还将研究限制速率NER酶的表达和/或活性来修复丙烷加合物的变异机制。总而言之，该项目获得的数据将有助于阐明内源性DNA损伤（氧化碱和环状DNA加合物）的作用，以及它们在突变和肝癌发生中的修复。