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: 10656535
• 负责人: Roderick O'Sullivan
• 金额: $ 36.08万
• 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/10656535
• 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 H3.3; Histones; Homeostasis; Impairment; Individual; Knowledge; Length; Licensing; Maintenance; Malignant Neoplasms; Measures; Mediator; Metabolism; Molecular; Molecular Chaperones; Mutate; Mutation; Nucleosomes; Optics; Pathway interactions; Patients; Phase; Poly Adenosine Diphosphate Ribose; Process; Prognosis; Proteomics; Recurrence; Regulation; Repair Complex; Repression; Research; Role; Serine; Stress; Structure; Telomere Maintenance; Telomere Pathway; Untranslated RNA; 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; 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变化才能存活。许多 最致命的癌症依赖于另一种端粒延长(ALT)端粒延长途径。 ALT与编码染色质修饰物的基因的反复突变密切相关，如ATRX- Daxx染色质重构/组蛋白沉积复合体。这些破坏了端粒染色质的组装， 引发复制应激和双链断裂(DSB)，刺激特定的同源DNA 修复(HDR)修复和延伸端粒的机制。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相关基因方面取得了重大进展 HDR(ALT-HDR)机制方面，ALT途径仍未被用于癌症治疗的开发。 染色质的单-ADP-核糖化(MAR化)最近已成为一个关键的传感器和 DNA损伤反应的发起者。MAR化主要发生在丝氨酸残基上并依赖于HPF1， 它与PARP1相互作用。组蛋白种子上特定丝氨酸的MAR化进一步PAR化 破坏DNA双链断裂(DSB)附近的核小体的稳定性，并允许招募第一个 DNA修复复合体的浪潮。ARH3是已知的唯一一种能够去除MAR的酶，该酶是由 HPF1-PARP1复合体。尽管有生化证据支持它在基因组维持中的基本作用， 丝氨酸MAR化的其他细胞靶点的识别及其放松调控的影响仍然不清楚。在……里面 目的1我们将评估ARH3和HPF1中断对ALT-HDR机制和ALT存活率的影响 癌细胞。在目标2中，我们将使用新的方法来追踪组蛋白在端粒沉积的过程 并评估这对Terra转录和ALT主要介体的招募的影响。 我们还将利用创新的蛋白质组学来确定MAR化的端粒靶标。圆满完成 这些目的的了解将有助于理解ALT-HDR期间这一重要的染色质标记及其 对癌细胞存活的影响。