Mutagenesis, tumorigenesis and human DNA polymerase epsilon

诱变、肿瘤发生和人类 DNA 聚合酶 epsilon

基本信息

批准号：
9252804
负责人：
Zachary F Pursell
金额：
$ 15万
依托单位：
TULANE UNIVERSITY OF LOUISIANA
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-06-01 至 2017-09-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9252804
关键词：
Address Affect Alleles Amino Acid Substitution Animal Model Automobile Driving Biochemical Biological Assay Biological Models Bypass Cancer Etiology Cell Culture Techniques Cells Collaborations Colorectal Neoplasms Complex DNA Damage DNA Polymerase II DNA Repair DNA Repair Gene DNA Sequence Alteration DNA biosynthesis DNA lesion DNA replication fork DNA-Directed DNA Polymerase Data Defect Development Disease Environment Environmental Risk Factor Enzymes Exonuclease Functional disorder Future Gene Silencing Genetically Engineered Mouse Genome Genome Stability Genomic Instability Genomics Goals Health Heavy Metals Holoenzymes Human Immune system In Vitro Kinetics Knowledge Laboratories Lead Malignant Neoplasms Metal exposure Metals Methods Mismatch Repair Missense Mutation Mission Modeling Mutagenesis Mutate Mutation Nonsense Mutation Pathway interactions Phosphodiesterase I Physiological Play Polymerase Positioning Attribute Research Research Design Resistance Role Site Somatic Mutation Testing Therapeutic Tumor Suppressor Genes Tumor Suppressor Proteins Uterine Neoplasms Work base burden of illness cancer cell cancer genome cancer type human DNA in vivo innovation insight interdisciplinary approach mouse model mutant novel novel therapeutic intervention polymerization prevent sugar tumor tumorigenesis

项目摘要

DESCRIPTION (provided by applicant): Normal somatic human cells are genetically stable and have a very low spontaneous mutation rate. In contrast, cancer cells are typically genetically unstable and accumulate thousands to hundreds of thousands of mutations in their genome. While it is known that DNA polymerase proofreading contributes to the accuracy of replication, several critical questions regarding how the loss of the proofreading function contributes to cancer remain unanswered: (1) What are the mechanisms through which proofreading dysfunction contributes to genome instability? (2) What extent do defects in polymerase proofreading play in driving cancer? and (3) To what extent do environmental factors like metal exposure influence polymerase-dependent tumor development? Here we provide evidence that cancer-associated mutations in human DNA polymerase (Pol) ε, a major replicative DNA polymerase, impair its proofreading activity, cause an increase in a unique type of mutagenesis and provide a survival advantage during metal exposure. We hypothesize that these effects have a direct influence on tumorigenesis. The main goal of this project is to test our central hypothesis that somatic mutations in Pol ε provide a selective advantage to tumor development through several, non-exclusive mechanisms, including (1) the accumulation of inactivating nonsense mutations in tumor suppressor genes; (2) resistance to oxidizing DNA damaging agents, including heavy metal exposure. This hypothesis is based on our preliminary data. Specifically, this project will 1) Establish a kinetic basis for cancer-causing Pol ε mutant alleles; 2) Define the mechanisms through which Pol ε exonuclease domain mutations (EDMs) generate their unique mutational signatures; and 3) Determine the mechanisms through which mutations in Pol ε contribute to tumor development. The proposed research is innovative due to the multidisciplinary approach that combines in vitro and in vivo studies to characterize the effects of cancer-associated Pol ε mutations on genome stability. The novel insights into how defects at the replication fork can influence genomic alterations are also innovative. This contribution is significant because it will provide new and detailed insights into the biochemical mechanisms of how replicative DNA polymerases normally prevent the acquisition of the complex diversity of mutations found in cancer genomes, as well as provide insights into the fundamental mechanisms of DNA replication. This knowledge will deepen our understanding of cancer development and can ultimately serve to inform future studies designed to modulate DNA polymerase activities toward the goal of novel cancer therapeutic strategies.

描述（由适用提供）：正常的体细胞细胞在遗传上是稳定的，并且赞助突变率非常低。相比之下，癌细胞通常在遗传上不稳定，并在其基因组中加速了数千至数十万个突变。虽然众所周知，DNA聚合酶校对有助于复制的准确性，但有关校对功能损失如何导致癌症的几个关键问题仍未得到解答：（1）校对功能障碍的机制是什么，导致基因组不稳定性？（2）聚合酶校对癌症中的缺陷在多大程度上？（3）金属暴露等环境因素在多大程度上影响聚合酶依赖性肿瘤的发展？在这里，我们提供了证据表明，人DNA聚合酶（POL）ε（一种主要的复制性DNA聚合酶）中与癌症相关的突变会损害其校对活性，导致独特类型的诱变类型的增加，并在金属暴露期间提供生存优势。我们假设这些作用对肿瘤发生直接影响。该项目的主要目的是检验我们的中心假设，即POLε中的体细胞突变通过多种非排他性机制为肿瘤发育提供了选择性优势，包括（1）肿瘤抑制基因中灭绝胡说突变的积累；（2）抗氧化DNA破坏剂的耐药性，包括重金属暴露。该假设基于我们的初步数据。具体而言，该项目将1）为引起癌症的Polε突变体建立动力学基础等位基因； 2）定义Polε外切核酸酶突变（EDM）产生其独特的突变特征的机制； 3）确定Polε突变有助于肿瘤发育的机制。拟议的研究具有创新性，这是因为多学科方法结合了体外和体内研究，以表征与癌症相关的POLε突变对基因组稳定性的影响。关于复制叉上缺陷如何影响基因组改变的新颖见解也是创新的。这项贡献很重要，因为它将提供有关复制性DNA聚合酶通常如何阻止癌症基因组中发现的复杂多样性的生化机制的新的和详细的见解，并提供了对DNA重复的基本机制的见解。这些知识将加深我们对癌症发展的理解，并最终可以为未来的研究提供旨在调节DNA聚合酶活性的研究，以实现新颖的癌症治疗策略。