Lipid peroxidation product induced DNA damage in the p53 gene and liver cancer

脂质过氧化产物诱导 p53 基因 DNA 损伤和肝癌

基本信息

批准号：
7668030
负责人：
Eric Moon-shong M. TANG
金额：
$ 36.16万
依托单位：
NEW YORK UNIVERSITY SCHOOL OF MEDICINE
依托单位国家：
美国
项目类别：
财政年份：
2006
资助国家：
美国
起止时间：
2006-09-28 至 2011-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7668030
关键词：
2-butenal Acrolein Address Aflatoxin B1 Aldehydes Alleles Amino Acids Base Excision Repairs Binding Cell physiology Cells Cirrhosis Code Codon Nucleotides Colon DNA DNA Adducts DNA Binding DNA Damage DNA Repair DNA Repair Inhibition DNA Sequence Disease Epidemiologic Studies Epithelial Cells Exons Gene Mutation Genetic Transcription Genomics Hepatitis Hepatitis B Virus Hepatocarcinogenesis Hepatocyte Human Incidence Induced Mutation Ligation Lipid Peroxidation Liver Malignant Neoplasms Malignant neoplasm of liver Malignant neoplasm of lung Malondialdehyde Mammalian Cell Maps Mediating Methods Modeling Modification Molecular Conformation Moon Mutation Mutation Detection Nuclear Nucleotide Excision Repair Nucleotides Oxidative Stress Pathogenesis Pathway interactions Physiological Play Polymerase Chain Reaction Primary carcinoma of the liver cells Process Protein Isoforms Protein p53 Proteins Rattus Reactive Oxygen Species Reporting Research Personnel Role Shapes Shuttle Vectors Simian B disease Site Smoke Specificity Staging Study models Sulfhydryl Compounds Surgical incisions TP53 gene Techniques Testing Thioredoxin Time Tobacco Virus Diseases Xenobiotics adduct base carcinogenesis choline deficient diet cytotoxic gain of function genotoxicity in vivo oxidative DNA damage programs protein misfolding repaired thioredoxin reductase

项目摘要

DESCRIPTION (provided by applicant): Hepatocellular carcinoma (HCC) is a major malignancy worldwide. Epidemiological studies have suggested that hepatitis B virus infection and dietary aflatoxin B1 (AFB1) are the two major etiological agents for human HCC. However, the underlying mechanisms of how these two agents induce hepatocarcinogenesis remain unclear. In rats HCC can be induced by a choline-deficient diet (CDD). The pathogenesis of CDD-induced HCC in rats mimics the pathogenesis of human HCC: hepatitis at an early stage, followed by steatosis, cirrhosis and finally HCC. Rats on CDD therefore provide an excellent model for studying HCC. It has been found that the lipid peroxidation (LPO) level and LPO product-induced DNA damage are significantly increased in liver cells of rats on CDD; LPO has thus been suspected of playing an important role in hepatocarcinogenesis. LPO is a cellular process that commonly takes place under normal physiological conditions, and this process becomes significant when cells are under oxidative stress. LPO generates a variety of aldehydes, such as acrolein (Acr), crotonaldehyde, malondialdehyde (MDA), and trans-4-hydroxy- 2-nonenal (4-HNE), that are able to interact with DNA; these adducts induce mainly G to T transversion. Aldehydes are also able to interact with proteins with a thiol group. We have recently found that 4-HNE and MDA are able to significantly inhibit cellular nucleotide excision repair (NER). Based on these results we hypothesize that these aldehydes may play important roles in carcinogenesis through two effects: induction of mutations by their interactions with DNA and inhibition of DNA repair by their interactions with repair proteins. By mapping the 4-HNE-DNA adduct distribution at the sequence level in human p53 gene fragments and genomic DNA we have found that 4-HNE preferentially binds to -GAGGC/A- sequences, including codon 249 of the p53 gene, the sole mutational hotspot in liver cancer. Our results raise the strong possibility that 4-HNE may play a particularly important role in hepatocarcinogenesis in both rats and humans. We propose to test these hypotheses using both the rat and cultured human hepatocyte model. We will determine how 4-HNE-DNA adducts in the p53 gene are processed, and the role of the p53 gene in aldehyde-mediated inhibition of DNA repair in human cells. We will also determine the effect of CDD on the repair capacity in rat liver cells, the formation of 4-HNE- and other aldehyde-induced DNA adducts formed in the p53 gene and the p53 mutational spectrum in CDD-induced HCC in rats. In addition, we will determine the effect of stereostructure of 4-HNE-dG at GAGGC sites on repair and mutagenicity. Results from these studies should greatly enhance our understanding of the role of LPO in hepatocarcinogenesis.

描述（由申请人提供）：肝细胞癌（HCC）是世界范围内的主要恶性肿瘤。流行病学研究表明，乙型肝炎病毒感染和膳食黄曲霉毒素B1（AFB1）是人类肝癌的两个主要病因。然而，这两种药物诱发肝癌的潜在机制仍不清楚。在大鼠中，缺乏胆碱的饮食（CDD）可诱发 HCC。 CDD诱导的大鼠肝癌的发病机制与人类肝癌的发病机制相似：早期为肝炎，随后是脂肪变性、肝硬化，最后是肝癌。因此，CDD 大鼠为研究 HCC 提供了一个极好的模型。研究发现，CDD组大鼠肝细胞中脂质过氧化（LPO）水平和LPO产物诱导的DNA损伤显着增加；因此，LPO被怀疑在肝癌发生中发挥重要作用。 LPO是正常生理条件下通常发生的细胞过程，当细胞处于氧化应激下时，该过程变得尤为重要。 LPO 产生多种能够与 DNA 相互作用的醛，如丙烯醛 (Acr)、巴豆醛、丙二醛 (MDA) 和反式 4-羟基-2-壬烯醛 (4-HNE)；这些加合物主要诱导 G 到 T 的转换。醛还能够与带有硫醇基团的蛋白质相互作用。我们最近发现4-HNE和MDA能够显着抑制细胞核苷酸切除修复（NER）。基于这些结果，我们假设这些醛可能通过两种作用在致癌过程中发挥重要作用：通过与 DNA 的相互作用诱导突变，以及通过与修复蛋白的相互作用抑制 DNA 修复。通过在人类p53基因片段和基因组DNA的序列水平上绘制4-HNE-DNA加合物分布图，我们发现4-HNE优先结合-GAGGC/A-序列，包括p53基因的密码子249，唯一的突变肝癌的热点。我们的结果提出了 4-HNE 很可能在大鼠和人类肝癌发生中发挥特别重要作用的可能性。我们建议使用大鼠和培养的人肝细胞模型来检验这些假设。我们将确定 p53 基因中的 4-HNE-DNA 加合物是如何加工的，以及 p53 基因在醛介导的人类细胞 DNA 修复抑制中的作用。我们还将确定 CDD 对大鼠肝细胞修复能力、p53 基因中 4-HNE 和其他醛诱导的 DNA 加合物的形成以及 CDD 诱导的大鼠 HCC 中 p53 突变谱的影响。此外，我们将确定 GAGGC 位点的 4-HNE-dG 立体结构对修复和致突变性的影响。这些研究的结果应该会极大地增强我们对 LPO 在肝癌发生中的作用的理解。