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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DNA双链断裂（DSB）未被修复或修复执行不正确，那么DNA双链断裂（DSB）是基因组中最致命的损伤之一。大多数癌症疗法（包括放射疗法）会诱导多个 DSB 来杀死癌细胞，但在非肿瘤细胞中同时诱导 DSB 可能会导致染色体重排，这可能是治疗患者中与治疗相关的肿瘤的来源。 DSB 修复通过两条主要途径进行，即同源定向修复 (HDR) 和非同源末端连接 (NHEJ)，这两条途径经过仔细调节以避免染色体畸变的形成。 DSB 修复调控对人类健康非常重要，因为 DSB 修复途径选择错误会引发促进癌症的基因重排，而错误的 DSB 修复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对DSB修复的调节，53BP1是一种DNA损伤反应因子，影响HDR和NHEJ之间的选择，促进NHEJ并抑制HDR。 53BP1 最近引起了人们的关注，因为它参与了用在 S/G2 中产生 DSB 的 PARP 抑制剂 (PARPi) 治疗 BRCA 缺陷的乳腺癌和卵巢癌。 Brca1 缺陷细胞对 PARPi 治疗敏感，因为它们无法通过同源重组 (HR) 修复 PARPi 诱导的 DSB，并积累由 NHEJ 形成的异常连接的致死染色体。然而，当 53BP1 缺失时，NHEJ 的不适当 DSB 修复就会减弱，HR 似乎会恢复，并且 PARPi 治疗不再有效。该提案旨在阐明 53BP1 控制 NHEJ 和 HDR 之间平衡的机制。我们建议使用我们实验室开发的基于端粒的检测系统的独特方面来确定 53BP1 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 DSB 处的 CtIP 依赖性切除，以及这种 DSB 修复调节途径的后果是什么，包括在 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 损伤位点/附近染色质移动性的能力，这是我们在端粒功能障碍的背景下发现的属性。 53BP1 改变染色质运动的机制将被确定，我们将解决该途径在多大程度上影响全基因组 DSB 的修复。这些实验旨在深入了解 53BP1 调节 DSB 修复的基本方面，最终目标是为使用 PARP 抑制剂治疗乳腺癌和卵巢癌以及其他癌症疗法（包括放射治疗）提供有价值的信息，其中 DSB 修复对治疗结果至关重要。