GENETIC DAMAGE BY LIPID PEROXIDATION

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。大量研究表明，脂质过氧化是人类癌症发生发展的一个重要因素。脂质过氧化过程中活性羰基化合物的持续产生也可能导致突变和癌症发病率的年龄相关性增加。脂质过氧化产物的致突变和促癌作用的DNA损伤的性质目前还不清楚。我们发现，体内培养的人细胞或大鼠肝脏中脂质过氧化的激活导致了与主要组蛋白的广泛的DNA交联。一些交联物被确定为对人类细胞具有致突变性。这些发现使我们能够提出这样的假设，即DNA-组蛋白交联物代表了人类细胞中由脂质过氧化形成的一类主要的致突变和遗传毒性DNA损伤。为了确定DNA-组蛋白交联物的生物学意义，我们提出了一系列研究，包括：(1)这些损伤激活的应激信号反应；(2)单个DNA-组蛋白交联物及其修复中间体的致突变和遗传毒性特性；(3)主要脂质过氧化产物在DNA-蛋白质交联物中的作用。这些研究结果将有助于阐明脂质过氧化所致遗传损伤的分子机制，并有助于更好地理解内源性DNA损伤的本质。DNA-组蛋白交联物生物学意义的建立将为其作为分子生物标记物用于评价饮食因素和化学预防药物改善脂质过氧化依赖的DNA损伤提供基础。

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. A large number of studies have strongly implicated lipid peroxidation as a significant factor in the development of human cancers. Continuous production of reactive carbonyl compounds by the lipid peroxidation process can also contribute to age-dependent increases in mutations and cancer incidence. The nature of the DNA damage responsible for the mutagenic and cancer-promoting effects of lipid peroxidation products is currently not well understood. We have found that activation of lipid peroxidation in cultured human cells or rat liver in vivo led to extensive formation of DNA crosslinks with major histone proteins. Some of the crosslinks were determined to be mutagenic in human cells. These findings allowed us to propose the hypothesis that DNA-histone crosslinks represent a major class of mutagenic and genotoxic DNA lesions formed by lipid peroxidation in human cells. To determine the biological significance of DNA-histone crosslinks, we propose a series of studies that will examine (1) stress signaling responses activated by these lesions, (2) mutagenic and genotoxic properties of individual DNA-histone crosslinks and their repair intermediates, and (3) the role of major lipid peroxidation products in DNA-protein crosslinking. The results of the proposed studies will help elucidate molecular mechanisms of genetic damage by lipid peroxidation and contribute to a better understanding of the nature of the endogenous DNA damage. Establishment of the biological significance of DNA-histone crosslinks would provide the basis for their use as molecular biomarkers in the evaluation of dietary factors and chemopreventive agents in the amelioration of lipid peroxidation-dependent DNA damage.