Mechanisms of genome instability induced by APOBEC Cytidine Deaminases and its impacts during cancer development.

APOBEC 胞苷脱氨酶诱导的基因组不稳定机制及其在癌症发展过程中的影响。

基本信息

批准号：
9919517
负责人：
STEVEN A ROBERTS
金额：
$ 38.66万
依托单位：
WASHINGTON STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-06-15 至 2022-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9919517
关键词：
Address Affect Bioinformatics Bypass Cancerous Cell Proliferation Cells Chemical Exposure Chemicals Chromatin Chromatin Remodeling Factor Chromosomal Rearrangement Copy Number Polymorphism Cytidine Cytidine Deaminase DNA DNA Double Strand Break DNA Sequence DNA Sequence Alteration DNA metabolism Deamination Defect Development ERBB2 gene Enzymes Event Family Frequencies Genetic Genetic Recombination Genome Genomic Instability Genotype Human Immune system Induced Mutation Innate Immune System Lead Lesion Malignant Neoplasms Measures Mediator of activation protein Molecular Mus Mutagenesis Mutation Oncogenes Phenotype Play Point Mutation Primary Neoplasm Reporting Retrotransposon Role Single-Stranded DNA Site Viral Work Yeast Model System Yeasts base cancer cell cancer genome carcinogenesis chemical genetics chromatin modification chromatin remodeling experimental study lipid metabolism malignant breast neoplasm mouse model overexpression replication stress tumor tumor progression tumorigenesis

项目摘要

Abstract APOBEC family cytidine deaminases are prominent mutators of cancer genomes, often causing thousands of C to T base substitutions in affected tumors. These enzymes normally function within the immune system and lipid metabolism. How APOBECs become dysregulated and the role subsequent of APOBEC-induced genetic instability has in promoting cancer progression are unclear. Also unknown is whether APOBECs induce other types of genetic instability in tumors in addition to base substitutions caused by deamination. The overall objective of this proposal is to identify mechanisms that enable APOBEC mutagenesis, determine how this activity alters cancer genomes, and assess the contribution of this genetic instability to carcinogenesis. Aim 1 will determine if increased levels of single strand DNA caused by chemical and oncogene-induced replication stress facilitates APOBEC mutagenesis. We will measure the effects of replication stress on APOBEC-induced mutation frequencies in human cells, determine if cancer cells displaying endogenous APOBEC activity also display markers of replication stress, and determine whether replication stress induced by Her2 activation synergizes with APOBEC mutagenesis to alter cell proliferation and accelerate tumorigenesis in a mouse model. Aim 2 will address how deficiencies in chromatin modifiers influence APOBEC mutagenesis. We have determined that loss of chromatin modifying enzymes, which are also frequently inactivated during cancer development, increase the frequency of APOBEC-induced mutations in yeast. The mechanisms underlying this effect will be determined and re-capitulated in human cells. Additionally, associations between chromatin modifier loss and elevated numbers of APOBEC-induced mutations in sequenced cancers will be bioinformatically evaluated. Aim 3 will investigate whether APOBECs are capable of inducing chromosomal rearrangements during cancer development. We will measure APOBEC-induced frequencies of non-allelic recombination and copy number variation in yeast and human cells as well as evaluate whether APOBECs mutagenize the single strand DNA intermediates formed during these recombination events to cause kataegis. The results from the experiments proposed in these Aims will likely demonstrate that mutation-driven, cancer-associated changes in DNA metabolism increase APOBEC- induced mutagenesis, investigate an expanded role for APOBECs in promotion of additional types of genetic alterations, and directly characterize the ability of APOBEC-generated mutagenesis to promote tumorigenesis. Successful completion of these aims will describe a critical aspect in the development and progression of a significant number of human tumors.

抽象的 APOBEC 家族胞苷脱氨酶是癌症基因组的重要突变体，通常会导致受影响的肿瘤中存在数千个 C 碱基替换为 T 碱基替换。这些酶通常在免疫系统和脂质代谢。 APOBECs 如何失调以及随后的作用 APOBEC 诱导的遗传不稳定性是否会促进癌症进展尚不清楚。还未知的是除了碱基替换之外，APOBEC 是否还会诱导肿瘤中其他类型的遗传不稳定性通过脱氨作用。该提案的总体目标是确定使 APOBEC 能够实现的机制诱变，确定这种活动如何改变癌症基因组，并评估这种遗传的贡献致癌作用不稳定。目标 1 将确定单链 DNA 水平的增加是否由化学物质引起癌基因诱导的复制应激促进 APOBEC 突变。我们将衡量以下效果复制压力对 APOBEC 诱导的人类细胞突变频率的影响，确定癌细胞是否显示内源性 APOBEC 活性还显示复制应激标记，并确定是否 Her2 激活诱导的复制应激与 APOBEC 突变协同作用，改变细胞增殖并加速小鼠模型中的肿瘤发生。目标 2 将解决染色质修饰剂的缺陷影响 APOBEC 诱变。我们已经确定染色质修饰酶的丢失，这些酶是在癌症发展过程中也经常失活，增加 APOBEC 诱导突变的频率在酵母中。这种效应背后的机制将在人类细胞中得到确定和重现。此外，染色质修饰剂丢失与 APOBEC 诱导的数量增加之间的关联将对已测序的癌症中的突变进行生物信息学评估。目标 3 将调查 APOBEC 是否能够在癌症发展过程中诱导染色体重排。我们将测量 APOBEC 诱导的酵母和人类非等位基因重组频率和拷贝数变异细胞并评估 APOBEC 是否诱变在过程中形成的单链 DNA 中间体这些重组事件引起kataegis。这些目标中提出的实验结果将可能表明突变驱动的、与癌症相关的 DNA 代谢变化会增加 APOBEC- 诱导突变，研究 APOBEC 在促进其他类型遗传性状中的扩大作用改变，并直接表征 APOBEC 产生的诱变促进肿瘤发生的能力。成功完成这些目标将描述一个发展和进步的关键方面大量的人类肿瘤。