Regulation of DSB repair by 53BP1

53BP1 对 DSB 修复的调节

基本信息

批准号：
8968823
负责人：
Titia de Lange
金额：
$ 45.71万
依托单位：
ROCKEFELLER UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-12-15 至 2016-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8968823
关键词：
Address Affect Attention BRCA1 gene Binding Biological Assay Breast Cancer Treatment Cancer Etiology Cell Cycle Stage Cells Chromatin Chromosome Structures Chromosome abnormality Chromosomes Complex Cytoplasm DNA DNA Damage DNA Repair DNA Repair Pathway Data Dependence Development Embryo Equilibrium Excision Fibroblasts Functional disorder Gene Rearrangement Genetic Engineering Genome Health Human Ionizing radiation Kinesin Laboratories Lesion Link Malignant Neoplasms Malignant neoplasm of ovary Mediating Membrane Proteins Microtubules Movement Mus Nonhomologous DNA End Joining Nuclear Pathway interactions Patients Peptide Hydrolases Proteins Radiation therapy Regulation Regulatory Pathway Repression Signal Transduction Site Source System Treatment outcome Treatment-Associated Neoplasms base cancer cell cancer therapy cell killing chemotherapeutic agent design genetic approach genome-wide homologous recombination inhibitor/antagonist insight killings malignant breast neoplasm nuclease p53-binding protein 1 recombinase repaired research study response telomere

项目摘要

DESCRIPTION (provided by applicant): Double-strand breaks in DNA (DSBs) are among the most lethal lesions in the genome if they are not repaired or if their repair is executed incorrectly. Most cancer therapies, including radiation therapy, induces multiple DSBs to kill cancer cells but concurrent induction of DSBs in non-tumor cells can result in chromosome rearrangements that might be a source of therapy related tumors in treated patients. DSB repair takes place through two main pathways, homology-directed repair (HDR) and non-homologous end-joining (NHEJ) that are carefully regulated to avoid the formation of chromosomal aberrations. DSB repair regulation is of great importance to human health since errors in the choice of DSB repair pathway can incite gene rearrangements that promote cancer and faulty DSB repair often generates aberrant chromosomal structures that kill cells. This proposal is focused on the regulation of DSB repair by 53BP1, a DNA damage response factor that affects the choice between HDR and NHEJ, promoting NHEJ and inhibiting HDR. 53BP1 has recently attracted attention because of its involvement in the treatment of BRCA-deficient breast and ovarian cancers with PARP inhibitors (PARPi) that generate DSBs in S/G2. Brca1-deficient cells are sensitive to PARPi treatment because they fail to repair PARPi-induced DSBs by homologous recombination (HR) and accumulate aberrantly linked lethal chromosomes formed by NHEJ. However, when 53BP1 is absent, inappropriate DSB repair by NHEJ is diminished, HR appears to be restored, and the PARPi treatment is no longer effective. This proposal aims to elucidate the mechanisms by which 53BP1 controls the balance between NHEJ and HDR. We propose to use unique aspects of a telomere-based assay system developed in our laboratory to determine the mechanism and consequences of three functional aspects of 53BP1. In AIM 1, we will ask how the 53BP1-interacting factor Rif1 inhibits CtIP-dependent resection at DSBs and what the consequences are of this regulatory pathway for DSB repair, including in PARPi-treated Brca1-deficient cells. In AIM 2, we will use a second, newly-developed telomere-based system to determine how 53BP1 inhibits a 5' resection pathway that is independent of CtIP. Finally, in AIM 3, we will focus on the ability of 53BP1 to increase the mobility of chromatin at/near sites of DNA damage, an attribute we discovered in the context of telomere dysfunction. The mechanism by which 53BP1 acts to change chromatin movement will be determined and we will address to what extent this pathway affects the repair of genome-wide DSBs. The experiments are designed to gain insights into fundamental aspects of the regulation of DSB repair by 53BP1 with the ultimate objective to provide information valuable to the use of PARP inhibitors for the treatment of breast and ovarian cancer and other cancer therapies, including radiation therapy in which DSB repair is central to the treatment outcome.

描述（由申请人提供）：如果未修复或修复其修复，DNA中的双链断裂（DSB）是基因组中最致命的病变之一。大多数包括放射治疗在内的癌症疗法都会诱导多个DSB杀死癌细胞，但同时诱导非肿瘤细胞中DSB的诱导可能会导致染色体重排，这可能是治疗患者与治疗相关的肿瘤的来源。 DSB修复是通过两种主要途径进行的，即同源指导修复（HDR）和非同源最终结合（NHEJ），它们经过仔细的调节，以避免形成染色体畸变。 DSB修复调节对人类健康至关重要，因为在选择DSB修复途径中的错误会促进促进癌症和DSB修复错误的基因重排，通常会产生杀死细胞的异常染色体结构。该提案的重点是53BP1的DSB修复，这是一个DNA损伤响应因子，影响HDR和NHEJ之间的选择，促进NHEJ和抑制HDR。 53BP1最近引起了人们的关注，因为它参与了缺乏BRCA的乳腺癌和卵巢癌的治疗，并用PARP抑制剂（PARPI）在S/G2中产生DSB。缺乏BRCA1的细胞对PARPI治疗很敏感，因为它们无法通过同源重组（HR）修复PARPI诱导的DSB，并积累了由NHEJ形成的异常连接的致命染色体。但是，当缺乏53BP1时，NHEJ的不适当DSB修复会减少，HR似乎已恢复，并且PARPI处理不再有效。该建议旨在阐明53BP1控制NHEJ和HDR之间的平衡的机制。我们建议使用在实验室开发的基于端粒的测定系统的独特方面，以确定53BP1的三个功能方面的机制和后果。在AIM 1中，我们将询问53BP1相互作用因子RIF1如何抑制DSBS处的CTIP依赖性切除，以及该调节性修复的调节途径的后果是什么，包括在Parpi-Parpi处理的BRCA1缺陷细胞中。在AIM 2中，我们将使用第二个新开发的基于端粒的系统来确定53BP1如何抑制独立于CTIP的5'切除途径。最后，在AIM 3中，我们将重点关注53BP1增加DNA损伤位置/附近染色质的迁移率的能力，DNA损伤的位置/附近，这是我们在端粒功能障碍背景下发现的属性。将确定53BP1改变染色质运动的机制，我们将在何种程度上解决该途径影响全基因组DSB的修复。该实验旨在洞悉53BP1调节DSB修复的基本方面，其最终目的是提供对使用PARP抑制剂用于治疗乳腺癌和卵巢癌和其他癌症疗法的信息，其中包括放射治疗，包括DSB修复是DSB修复是治疗结果的中心。