Role of Aflatoxin-induced DNA Damage Formation and Repair in Hepatic Mutagenesis

摘要/项目摘要 黄曲霉毒素是由真菌黄曲霉和寄生曲霉产生的一种广为人知的 一种环境致癌物质，可导致突变并最终导致肝细胞癌 是全球癌症死亡的主要原因之一。饮食中长期摄入黄曲霉毒素B1(AFB1)最多 致突变黄曲霉毒素和慢性感染乙肝病毒(乙肝病毒)或丙型肝炎病毒(丙型肝炎病毒)是 肝细胞癌发生的两个主要病因。核苷酸切除修复是修复机制 通过这种方式，由AFB1诱导的巨大损伤被从基因组中移除。尽管我们的工作取得了进展 了解黄曲霉毒素B_1-DNA加合物，整个过程中巨大DNA损伤的形成和清除动力学 基因组和影响损伤形成和修复效率的因素仍然难以捉摸。我们的长期合作 这个项目的目标是更好地了解AFB1诱导的DNA损伤形成和修复的动力学 对人类肝脏的诱变有贡献。这项特别提案的总体目标是一个初步的 实现我们长期目标的一步，是将生物化学、遗传学、内收学和计算结合起来 研究组蛋白修饰和三维(3D)基因组组织影响的方法 黄曲霉毒素B_1诱导DNA损伤的形成和修复，并确定黄曲霉毒素B_1与DNA的相关性 人肝细胞癌AFB1的加合谱或修复效率及突变谱。我们的中心假设是 人肝细胞突变与黄曲霉毒素B_1诱导的DNA损伤形成和/或修复有关 事件，受组蛋白修饰和3D基因组组织的影响。我们提出了两个具体的 旨在验证我们的假设，并实现以下目标：1)！黄曲霉毒素B_1诱导的DNA全基因组分析 组蛋白修饰和3D基因组组织对损伤形成和修复动力学的影响 (Aim1、K99和R00阶段)。2)确定AFB1-DNA加合物光谱或修复之间的相关性 AFB1在人肝细胞癌(AIM2，R00期)中的效率和突变谱我们预计会出现以下情况 结果：确定组蛋白乙酰化对AFB1-DNA加合物形成和修复的影响 效率；测定3D基因组组织对AFB1-DNA加合物形成和修复的影响 AFB1诱导的癌症相关DNA损伤热点和修复冷点的鉴定 基因.黄曲霉毒素B_1-DNA加合物光谱或修复效率之间相关性的测定 AFB1在人肝细胞癌中的突变谱这项拟议的研究具有重要意义，因为它将提供见解 研究AFB1相关肝癌的发展，改进预防策略，开发更好的治疗方法 肝细胞癌。

ABSTRACT / PROJECT SUMMARY Aflatoxin, produced by the fungi Aspergillus flavus and Aspergillus parasiticus, is a well-known environmental carcinogen that causes mutations and ultimately leads to hepatocellular carcinoma (HCC), one of the leading causes of cancer deaths worldwide. Chronic dietary exposure to aflatoxin B1 (AFB1), the most mutagenic aflatoxin, and chronic infections with the hepatitis B virus (HBV) or hepatitis C virus (HCV) are the two major etiological factors for the development of HCC. Nucleotide excision repair is the repair mechanism by which the bulky lesions induced by AFB1 are removed from the genome. Despite the progress in our knowledge of the AFB1-DNA adduct, the formation and removal kinetics of the bulky DNA lesion throughout the genome and the factors affecting the damage formation and repair efficiency remain elusive. Our long-term goal of this project is to better understand how the kinetics of AFB1-induced DNA damage formation and repair contributes to human hepatic mutagenesis. The overall objective of this particular proposal, which is an initial step to achieve our long-term goal, is to combine biochemistry, genetics, adductomics and computational approaches to investigate effects of histone modifications and three-dimensional (3D) genome organization on AFB1-induced DNA damage formation and repair, and to determine the correlations between AFB1-DNA adduct spectra or repair efficiencies and mutational spectra of AFB1 in human HCC. Our central hypothesis is that human hepatic mutagenesis correlates with the AFB1-induced DNA damage formation and/or repair events, which are affected by histone modifications and 3D genome organization. We propose two specific aims to test our hypothesis and accomplish the objective: 1)! Genome-wide Analysis of AFB1-induced DNA Damage Formation and Repair Kinetics as a Function of Histone Modifications and 3D Genome Organization (Aim1, K99 and R00 phase). 2) Determine the Correlations Between AFB1-DNA Adduct Spectra or Repair Efficiencies and Mutational Spectra of AFB1 in Human HCC (Aim2, R00 phase). We expect the following outcomes: Determination of the effect of histone acetylation on AFB1-DNA adducts formation and repair efficiency; determination of the effect of 3D genome organization on AFB1-DNA adducts formation and repair efficiency; identification of AFB1-induced DNA damage hot spots and repair cold spots in cancer-associated genes; determination of the correlations between AFB1-DNA adduct spectra or repair efficiencies and mutational spectra of AFB1 in human HCC. The proposed research is significant because it will give insights into development of AFB1-associated HCC, improve prevention strategies and develop better treatment for HCC.