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

基本信息

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
项目类别：
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

项目摘要

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.

抽象的癌细胞必须激活端粒伸长机制，并获得基因组改变以生存。许多最致命的癌症中，端粒（ALT）端粒伸长途径的替代延长。 ALT与编码染色质修饰剂（例如Atrx-）的基因中的复发突变密切相关 DAXX染色质重塑/组蛋白沉积复合物。这些破坏了端粒染色质的组装，刺激专业同源性DNA的挑衅重复应力和双链断裂（DSB）修复（HDR）修复和扩展端粒的机制。因此，ALT途径代表一个宝贵的目标用于癌症治疗的发展。尽管在理解这些独特的Alt相关方面取得了重大进展 HDR（Alt-HDR）机制，ALT途径仍未用于癌症治疗的发展。染色质的单核-ribosylation（Marylation）最近出现为钥匙传感器和 DNA损伤反应的引发器。玛丽化主要发生在丝氨酸残基上，并依赖于HPF1，与PARP1相互作用。在组蛋白种子上的特定丝氨酸的玛丽化进一步抚养破坏与DNA双链断裂（DSB）近端的核小体的稳定稳定，并获得了第一个的招募 DNA修复复合物的波浪。 ARH3是唯一能够去除MAR合成的酶 HPF1-PARP1复合物。尽管生化证据支持其在基因组维持中的基本作用，但丝氨酸玛丽化的其他细胞靶标的身份及其放松管制的作用仍然晦涩难懂。在目标1我们将评估ARH3和HPF1破坏对ALT-HDR机制的影响和ALT的生存癌细胞。在AIM 2中，我们将采用新颖的方法来跟踪组蛋白，因为它们被存入端粒并评估这对Terra转录的影响和ALT主要调解人的招募。我们还将采用创新的蛋白质组学来识别玛丽化的端粒靶标。成功完成这些目标将有助于理解Alt-HDR期间这种重要的染色质标记对癌细胞存活的影响。