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。

• 批准号: 9919034
• 负责人: STEVEN A ROBERTS
• 金额: $ 11.54万
• 依托单位: WASHINGTON STATE UNIVERSITY
• 依托单位国家: 美国
• 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/9919034
• 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; 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; Metabolism; 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

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突出突变器，通常引起 在受影响的肿瘤中成千上万的C碱取代。这些酶通常在 免疫系统和脂质代谢。 Apobec的失调以及随后的作用 APOBEC诱导的遗传不稳定性在促进癌症进展方面尚不清楚。也未知 除基地取代外，APOBEC是否在肿瘤中诱导其他类型的遗传不稳定性 通过脱氨酸。该提案的总体目的是确定使Apobec的机制 诱变，确定该活性如何改变癌症基因组并评估该遗传的贡献 致癌作用的不稳定性。 AIM 1将确定化学物质引起的单链DNA水平是否增加 癌基因诱导的复制应力促进了Apobec诱变。我们将衡量 对APOBEC诱导的人类细胞突变频率的复制应力，确定癌细胞是否是否 显示内源性APOBEC活性还显示复制应力标记，并确定是否是否 HER2激活引起的复制应力与Apobec诱变协同以改变细胞增殖 并在小鼠模型中加速肿瘤发生。 AIM 2将解决染色质修饰符中的缺陷 影响apobec诱变。我们已经确定染色质修饰酶的损失是 在癌症发展过程中也经常灭活，增加APOBEC诱导的突变的频率 在酵母中。该作用的基础机制将在人类细胞中确定和重新列出。 此外，染色质修饰剂损失与APOBEC诱导的数量升高之间的关联 测序癌症中的突变将对生物信息进行评估。 AIM 3将调查Apobecs是否 能够在癌症发展过程中诱导染色体重排。我们将衡量 酵母和人类的非平行性重组和拷贝数变化的APOBEC诱导的频率 细胞以及评估Apobecs是否诱变在此期间形成的单链DNA中间体 这些重组事件导致Kataegis。这些目标中提出的实验的结果将 可能表明，突变驱动的，与癌症相关的DNA代谢变化增加了Apobec- 诱导的诱变，研究APOBEC在促进其他类型的遗传方面的扩展作用 改变，并直接表征Apobec生成的诱变促进肿瘤发生的能力。 这些目标的成功完成将描述一个关键方面 大量人类肿瘤。