Compensatory mechanisms that promote homologous recombination in BRCA1 mutant cancers

促进 BRCA1 突变癌症同源重组的补偿机制

基本信息

批准号：
10242152
负责人：
Neil Johnson
金额：
$ 42.78万
依托单位：
RESEARCH INST OF FOX CHASE CAN CTR
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-09-01 至 2024-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10242152
关键词：
Address Alleles BARD1 gene BRCA mutations BRCA1 Mutation BRCA1 Protein BRCA1 gene BRCA2 Mutation BRCA2 gene Biological Assay Breast Bypass CRISPR/Cas technology Cancer cell line Cause of Death Cell Survival Cells Cessation of life Chemoresistance Chemosensitization Cisplatin Clinical DNA Double Strand Break DNA Repair Data Defect Development Direct Repeats Disease Resistance Drug resistance Embryo Enzymes Epithelial Cells Genes Genetic Germ-Line Mutation Goals Growth Heterodimerization Histones Human In Vitro Knock-out Length Loss of Heterozygosity Malignant Neoplasms Malignant neoplasm of ovary Measures Mediating Mus Mutation Ovarian PALB2 gene PARP inhibition Patients Platinum Prediction of Response to Therapy Primary Neoplasm Process Proteins Publishing RNA Interference Regulator Genes Reporter Residual state Resistance Role Signal Transduction Sister Chromatid System Testing Tumor Pathology Tumor Suppressor Genes Tumor-Derived Ubiquitin United States Work anti-cancer therapeutic base biomarker development cancer cell cancer genome cancer initiation cancer therapy cell type experimental study genetic manipulation homologous recombination in vivo inhibitor/antagonist knockout gene malignant breast neoplasm mutant mutation carrier novel overexpression patient derived xenograft model pressure protein expression protein function recombinational repair response therapy resistant transcriptome tumor tumor growth tumor initiation ubiquitin ligase ubiquitin-protein ligase

项目摘要

PROJECT SUMMARY The BRCA1 protein functions in homologous recombination (HR), a DNA repair process that uses the undamaged sister chromatid to carry out high fidelity repair of DNA double strand breaks (DSBs). Genetic knockout of HR genes in mice demonstrated that Brca1 and the process of HR are critical for viability. In contrast, loss of the BRCA1 wild-type allele provides a growth advantage and cells are positively selected during cancer initiation in patients with germline BRCA1 mutations. In our preliminary analyses, we show that the BRCA1 mutant allele is invariably retained in cancers derived from patients with germline mutations. Interestingly, Brca1 mutant alleles have been shown to prolong embryonic viability in Brca1 null backgrounds, suggesting partial rescue of full-length Brca1 activity. In our recently published studies, we show that BRCA1 mutant alleles are capable of generating truncated proteins and promote residual HR in BRCA1 mutant cancers. In this proposal, we will investigate the importance of BRCA1 mutant alleles and HR for cell and tumor viability in BRCA1 mutant cancers. Furthermore, cells that are deficient in HR DNA repair, such as those lacking functional BRCA1 or BRCA2, are highly sensitive to platinum and PARP inhibition (PARPi). However, emerging data indicate that PARPi therapy may benefit only a subset of BRCA1 mutation carriers. In the second part of this proposal, we will uncover mechanisms that elevate HR to a level required for platinum and PARPi resistance. We show that proteins generated from BRCA1185delAG and BRCA1C61G alleles fail to interact with BARD1, lack ubiquitin ligase activity, and are only capable of providing moderate platinum and PARPi resistance. We hypothesize that BRCA1-BARD1 ubiquitin ligase activity is important for more robust levels of HR that is necessary for therapy resistance. In preliminary data, we identified RNF7 and RNF207 as novel ubiquitin regulators that demonstrated increased expression in PARPi resistant BRCA1185delAG and BRCA1C61G clones, and compensate for ubiquitin ligase deficient-BRCA1 proteins. We will manipulate the expression of ubiquitin ligase proteins and measure DNA repair, PARPi and cisplatin sensitivity in vitro and in vivo. Proteins that contribute to resistance will be assessed for expression in PDX models as well as primary tumors. Using these approaches, we will address the following Specific Aims: 1) investigate the role of BRCA1 mutant alleles in maintaining HR and cancer viability; and 2) investigate HR-promoting mechanisms contributing to therapy resistance. Our work will ultimately contribute to the development of biomarkers that predict therapy response and reveal novel targets for chemo- sensitization.

项目概要 BRCA1 蛋白在同源重组 (HR) 中发挥作用，这是一种利用未受损的姐妹染色单体可对 DNA 双链断裂 (DSB) 进行高保真修复。遗传小鼠 HR 基因的敲除表明 Brca1 和 HR 过程对于生存能力至关重要。相比之下， BRCA1 野生型等位基因的缺失提供了生长优势，并且细胞在癌症过程中得到积极选择生殖系 BRCA1 突变患者的起始治疗。在我们的初步分析中，我们表明 BRCA1 突变等位基因总是保留在源自种系突变患者的癌症中。有趣的是，Brca1 突变等位基因已被证明可以在 Brca1 无效背景下延长胚胎活力，这表明部分拯救全长 Brca1 活性。在我们最近发表的研究中，我们表明 BRCA1 突变等位基因是能够产生截短的蛋白质并促进 BRCA1 突变癌症中的残留 HR。在这个提案中，我们将研究 BRCA1 突变等位基因和 HR 对 BRCA1 突变中细胞和肿瘤活力的重要性癌症。此外，HR DNA 修复缺陷的细胞，例如缺乏功能性 BRCA1 或 BRCA2 对铂和 PARP 抑制 (PARPi) 高度敏感。然而，新出现的数据表明 PARPi 疗法可能仅对一部分 BRCA1 突变携带者有益。在本提案的第二部分中，我们将揭示将 HR 提高到铂和 PARPi 耐药性所需水平的机制。我们表明 BRCA1185delAG 和 BRCA1C61G 等位基因生成的蛋白质无法与 BARD1 相互作用，缺乏泛素连接酶活性，并且只能提供中等的铂和 PARPi 电阻。我们假设 BRCA1-BARD1 泛素连接酶活性对于治疗所需的更稳定的 HR 水平非常重要反抗。在初步数据中，我们将 RNF7 和 RNF207 确定为新型泛素调节剂，证明了 PARPi 抗性 BRCA1185delAG 和 BRCA1C61G 克隆中的表达增加，并补偿泛素连接酶缺陷型 BRCA1 蛋白。我们将操纵泛素连接酶蛋白的表达并测量 DNA 修复、PARPi 和顺铂的体外和体内敏感性。有助于抵抗力的蛋白质是评估 PDX 模型以及原发性肿瘤中的表达。使用这些方法，我们将解决具体目标如下： 1) 研究 BRCA1 突变等位基因在维持 HR 和癌症活力中的作用； 2) 研究导致治疗抵抗的 HR 促进机制。我们的工作最终将有助于预测治疗反应并揭示化疗新靶标的生物标志物的开发敏化。

项目成果

期刊论文数量（1）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

RNF168-Mediated Ubiquitin Signaling Inhibits the Viability of BRCA1-Null Cancers.

RNF168 介导的泛素信号传导抑制 BRCA1 无效癌症的活力。

DOI：
发表时间：
2020
期刊：
影响因子：
11.2
作者：
Krais, John J;Wang, Yifan;Bernhardy, Andrea J;Clausen, Emma;Miller, Jessica A;Cai, Kathy Q;Scott, Clare L;Johnson, Neil
通讯作者：
Johnson, Neil