Restoring genome stability and tumor suppression in BRCA1 deficient cells

恢复 BRCA1 缺陷细胞的基因组稳定性和肿瘤抑制

• 批准号: 10064997
• 负责人: RICHARD J BAER
• 金额: $ 52.35万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10064997
• 关键词: Address; Animal Model; BRCA mutations; BRCA1 Mutation; BRCA1 Protein; BRCA1 gene; BRCA2 Protein; BRCA2 gene; Biological; Breast; Breast Carcinoma; Breast Epithelial Cells; Cell physiology; Cells; Chromosome abnormality; Chromosomes; Clinical; DNA; DNA Damage; DNA Double Strand Break; DNA biosynthesis; DNA replication fork; Data; Elements; G2 Phase; Genetically Engineered Mouse; Genome; Genome Stability; Genomic Instability; Germ-Line Mutation; Hereditary Breast Carcinoma; Hereditary Breast and Ovarian Cancer Syndrome; Inherited; Intervention; Lead; Lesion; Maintenance; Malignant Neoplasms; Malignant neoplasm of ovary; Mammary Neoplasms; Mediating; Mediator of activation protein; Modeling; Molecular; Mutant Strains Mice; Normal Cell; Ovarian; Pathogenicity; Pathway interactions; Patients; Predisposition; Process; Property; Proteins; S Phase; Serous; Testing; Therapeutic; Tumor Suppression; Tumor Suppressor Genes; Tumorigenicity; Woman; brca gene; ds-DNA; genome integrity; homologous recombination; in vivo; malignant breast neoplasm; mutant; mutation carrier; novel; nuclease; preservation; prophylactic; reconstitution; repaired; replication stress; response; therapeutic target; translocase; tumor; ubiquitin-protein ligase

PROJECT SUMMARY/ABSTRACT: As central mediators of the DNA damage response, the BRCA1 and BRCA2 proteins normally act to preserve genome integrity. Indeed, their genome maintenance functions are thought to be a major, if not the principal, means by which BRCA1/2 suppress tumor formation in normal cells. In particular, BRCA1 and BRCA2 are required for double-strand DNA break repair by homologous recombination (DSBR-HR). However, recent studies have uncovered another BRCA1/2 function that also preserves genome stability and thus potentially contributes to the tumor suppression activity of both proteins. During DNA replication, BRCA1 and BRCA2 have been shown to promote genome integrity by protecting stalled replication forks (SRFs) from nucleolytic degradation. These findings raise critical questions regarding the mechanisms of BRCA1/2 tumor suppression and the prospects for therapeutic targeting of the BRCA1/2 pathway. For example, is the tumor suppression activity of the BRCA1/2 pathway mediated through its ability to promote DSBR-HR or SRF stability, or both? Also, can the DSBR-HR or SRF stability functions of BRCA1/2 be restored for prophylactic and/or therapeutic purposes in women who carry BRCA1/2 mutations? Our preliminary studies have uncovered a novel mechanism by which SRF stability can be reconstituted in BRCA1 mutant cells. In particular, we show that depletion of SMARCAL1, a DNA translocase implicated in replication fork dynamics, restores both SRF stability and chromosome integrity in BRCA1-deficient cells subjected to replication stress. On the basis of these results, we hypothesize that inappropriate remodeling of replication forks by SMARCAL1 in BRCA1- deficient cells can increase genome instability and thereby predispose these cells to breast cancer. To test these hypotheses, we will 1) define the mechanisms by which SMARCAL1 inactivation rescues SRF stability and chromosomal integrity in BRCA1-deficient cells, and 2) determine whether tumor suppression activity can be restored to BRCA1-mutant cells by SMARCAL1 inhibition.

项目摘要/摘要： 作为DNA损伤响应的中央介体，BRCA1和BRCA2蛋白通常作用以保存 基因组完整性。确实，他们的基因组维持功能被认为是主要的，即使不是校长， BRCA1/2抑制正常细胞中肿瘤形成的方法。特别是，BRCA1和BRCA2是 通过同源重组（DSBR-HR）进行双链DNA断裂修复所需的。但是，最近 研究发现了另一种BRCA1/2功能，该功能也可以保留基因组稳定性，因此有可能 有助于两种蛋白质的肿瘤抑制活性。在DNA复制期间，BRCA1和BRCA2 已显示通过保护停滞的复制叉（SRF）免受核酸溶解来促进基因组完整性 降解。这些发现提出了有关BRCA1/2肿瘤抑制机制的关键问题 以及BRCA1/2途径的治疗靶向前景。例如，肿瘤抑制 BRCA1/2途径的活性是通过促进DSBR-HR或SRF稳定性的能力，还是两者兼而有之。 同样，可以恢复BRCA1/2的DSBR-HR或SRF稳定性功能，以进行预防和/或治疗 携带BRCA1/2突变的女性目的？我们的初步研究发现了一本小说 可以在BRCA1突变细胞中重构SRF稳定性的机制。特别是，我们表明 Smarcal1的耗竭是一种与复制叉动力学有关的DNA易位酶，恢复了两个SRF 受复制应力的BRCA1缺陷细胞中的稳定性和染色体完整性。基于 这些结果，我们假设Smarcal1在BRCA1-中对复制叉的不当重塑 缺乏细胞会增加基因组不稳定性，从而使这些细胞容易受到乳腺癌的影响。测试 这些假设，我们将1）定义smarcal1灭活的机制挽救SRF稳定性 BRCA1缺陷细胞中的染色体完整性，2）确定肿瘤抑制活性是否可以 通过SMARCAL1抑制恢复为BRCA1突变细胞。