Inhibition of the ALT pathway by interfering with Poly-ADP-Ribose metabolism

通过干扰聚 ADP 核糖代谢来抑制 ALT 途径

• 批准号: 10518557
• 负责人: Roderick O'Sullivan
• 金额: $ 36.82万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-01 至 2027-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10518557
• 关键词: ADP ribosylation; ATRX gene; Address; Adenosine Diphosphate Ribose; Affect; Biochemical; Biological Assay; Bypass; Cancer Etiology; Cancerous; Cell Survival; Cell division; Cells; Chromatin; Chromatin Modeling; Chromatin Remodeling Factor; Chromosomes; Complex; DAXX gene; DNA; DNA Damage; DNA Double Strand Break; DNA Repair; DNA Sequence Alteration; DNA biosynthesis; Deposition; Detection; Disease; Dissection; Ensure; Enzymes; Genes; Genetic; Genetic Transcription; Genome; Glycoside Hydrolases; Goals; Histone H3; Histones; Homeostasis; Impairment; Individual; Knowledge; Length; Licensing; Maintenance; Malignant Neoplasms; Measures; Mediator of activation protein; Metabolism; Molecular; Molecular Chaperones; Mutate; Mutation; Nucleosomes; Optics; Pathway interactions; Patients; Phase; Poly Adenosine Diphosphate Ribose; Process; Prognosis; Proteomics; Recurrence; Regulation; Repair Complex; Research; Role; Seeds; Serine; Structure; Telomere Maintenance; Telomere Pathway; Untranslated RNA; base; cancer cell; cancer prevention; cancer therapy; cellular targeting; chromatin modification; chromatin remodeling; defined contribution; histone modification; improved; innovation; mutant; novel strategies; poly ADPR glycohydrolase inhib; preservation; public health relevance; recruit; repaired; replication stress; response; sensor; synergism; targeted cancer therapy; telomere; therapeutic target; therapy development

ABSTRACT Cancer cells must activate a telomere elongation mechanism and acquire genomic alterations to survive. Many of the most lethal cancers rely on the Alternative Lengthening of Telomeres (ALT) telomere elongation pathway. ALT is strongly associated with recurrent mutations in genes encoding chromatin modifiers such as the ATRX- DAXX chromatin remodeling/histone deposition complex. These disrupt the assembly of telomeric chromatin, provoking replicative stress and double-strand breaks (DSBs) that stimulate specialized homology-directed DNA repair (HDR) mechanisms to repair and extend telomeres. Thus, the ALT pathway represents a valuable target for cancer therapy development. Despite significant advances in understanding these unique ALT-associated HDR (ALT-HDR) mechanisms, the ALT pathway remains unexploited for cancer therapy development. The mono-ADP-ribosylation (MARylation) of chromatin has recently emerged as a key sensor and initiator of the DNA damage response. MARylation predominantly occurs on serine residues and relies on HPF1, which interacts with PARP1. MARylation of specific serines on histones seeds further PARylation that destabilizes nucleosomes proximal to DNA double strand breaks (DSBs) and licenses the recruitment of the first wave of DNA repair complexes. ARH3 is the only known enzyme capable of removing MAR synthesized by the HPF1-PARP1 complex. Despite biochemical evidence supporting its fundamental role in genome maintenance, the identity of additional cellular targets of serine MARylation, and effects of its deregulation, remain obscure. In Aim 1 we will assess the impact of ARH3 and HPF1 disruption on ALT-HDR mechanisms and survival of ALT cancer cells. In Aim 2, we will employ novel approach to track histones as they are being deposited at telomeres and evaluate the impact that this has on transcription of TERRA and the recruitment of major mediators of ALT. We will also employ innovative proteomics to identify telomeric targets of MARylation. The successful completion of these aims will contribute to the understanding of this important chromatin mark during ALT-HDR and its impact on cancer cell survival.

摘要 癌细胞必须激活端粒延长机制并获得基因组改变才能生存。许多 大多数致命的癌症依赖于端粒替代延长（ALT）端粒延长途径。 ALT与编码染色质修饰剂（如ATRX-1）的基因的复发性突变密切相关。 DAXX染色质重塑/组蛋白沉积复合物。它们破坏了端粒染色质的组装， 引发复制应激和双链断裂（DSB），刺激专门的同源定向DNA 修复（HDR）机制来修复和延长端粒。因此，ALT途径是一个有价值的靶点， 用于癌症治疗的发展。尽管在理解这些独特的ALT相关的 HDR（ALT-HDR）机制，ALT途径仍然未被开发用于癌症治疗开发。 染色质的单ADP核糖基化（MARylation）最近已经成为关键的传感器， 启动DNA损伤反应。MAR化主要发生在丝氨酸残基上并依赖于HPF 1， 与PARP 1相互作用。组蛋白上的特定丝氨酸的MARylation导致进一步的PARylation， 使邻近DNA双链断裂（DSB）的核小体不稳定，并允许第一个 DNA修复复合物的浪潮。ARH 3是唯一已知的能够去除由ARH 3合成的MAR的酶。 HPF 1-PARP 1复合物。尽管生化证据支持它在基因组维护中的基本作用， 丝氨酸MARYLATION的其它细胞靶点的身份及其失调的作用仍然不清楚。在 目的1：我们将评估ARH 3和HPF 1破坏对ALT-HDR机制和ALT存活的影响。 癌细胞在目标2中，我们将采用新的方法来跟踪组蛋白沉积在端粒上的过程 并评估这对TERRA转录和ALT主要介质募集的影响。 我们还将采用创新的蛋白质组学，以确定端粒的MARylation目标。圆满完成 这些目标将有助于理解ALT-HDR过程中这一重要的染色质标记及其 对癌细胞存活的影响