DNA repair dysfunction in cancer induced by altered BRCA2 localization

BRCA2 定位改变引起的癌症 DNA 修复功能障碍

• 批准号: 10739521
• 负责人: Judit Jimenez Sainz
• 金额: $ 20.58万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-12 至 2026-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10739521
• 关键词: Affect; Antibodies; Award; Biochemistry; Biological; Biology; Breast Cancer Detection; Breast Cancer gene; C-terminal; Cancer Biology; Cancer Diagnostics; Cancer Etiology; Cancer Patient; Cancer-Predisposing Gene; Cell Nucleus; Cell model; Cellular biology; Centrosome; Chromosome Mapping; Clinical Management; Cytoplasm; Cytosol; DNA; DNA Binding Domain; DNA Damage; DNA Double Strand Break; DNA Repair; DNA Repair Gene; DNA Repair Pathway; DNA replication fork; Defect; Development; Double Strand Break Repair; Ensure; Family member; Frameshift Mutation; Functional disorder; Gene Expression; Gene Mutation; Genome Stability; Genomic Instability; Goals; Hereditary Breast and Ovarian Cancer Syndrome; Human; Institution; Knowledge; Lead; Malignant Neoplasms; Mass Spectrum Analysis; Measures; Missense Mutation; Molecular; Mutation; Nonsense Mutation; Normal Cell; Nuclear; Nuclear Import; Nuclear Localization Signal; Nuclear Protein; Oncogenes; Pancreas; Pathogenicity; Pathway interactions; Patients; Pharmaceutical Preparations; Platinum; Poly(ADP-ribose) Polymerase Inhibitor; Positioning Attribute; Postdoctoral Fellow; Prevention; Principal Investigator; Process; Proteins; Proteomics; Reporting; Research; Risk Assessment; Testing; Therapeutic Intervention; Time; Tissue Microarray; Tissue Sample; Treatment outcome; Tumor Tissue; Uncertainty; Variant; cancer cell; cancer genetics; cancer risk; carcinogenesis; career; clinical application; diagnostic tool; driver mutation; genetic testing; genetic variant; genome integrity; hereditary risk; human tissue; malignant breast neoplasm; melanoma; neoplastic cell; novel; nucleocytoplasmic transport; patient stratification; prevent; prostate cancer risk; protein folding; protein misfolding; reconstitution; repair function; repaired; response; risk stratification; skill acquisition; success; targeted cancer therapy; targeted treatment; therapy resistant; tool; trafficking; tumor; variant of unknown significance; virulence gene

PROJECT SUMMARY/ABSTRACT BRCA2, as part of the DNA repair pathway, is a key regulator in homology-directed repair (HDR) and fork protection mechanism, which ensures genome instability. For full activity, BRCA2 must be transported into the nucleus to repair DNA double-strand breaks (DSBs). In normal cells, loss of nuclear BRCA2 can lead to genome instability and cancer but, in tumor cells, BRCA2 cytosolic mislocalization can lead to sensitivity to targeted therapies. I identified a paradoxical relationship between BRCA2 nuclear import and treatment. Pathogenic missense mutations in the DNA binding domain of BRCA2 direct the protein to the cytosol which increase sensitivity to PARP inhibitors (PARPi) and platinum drugs. Therefore, although BRCA2 mislocalization might be a cause of cancer, keeping it out of the nucleus allows for much better treatment outcomes. This has opened an avenue of research that I am perfectly aligned to study. In this K22 proposal I will address the nuclear transport of BRCA2, how cancer-driver mutations lead to cytosolic mislocalization and how BRCA2 localization can be used as a diagnostic tool. To test this, I will define the molecular mechanism(s) regulating nuclear/cytoplasmic shuttling of BRCA2 pathogenic missense variants (Aim 1), determine the impact of BRCA2 cellular localization on HDR, fork protection and cytosolic processes (Aim 2) and exploit BRCA2 localization as a cancer diagnostic tool (Aim 3). My priority will be to focus on missense variants identified during my postdoctoral career to decipher the underlying molecular mechanism of nuclear/cytosolic BRCA2 trafficking. At the successful completion of this K22 proposal, I will reveal novel pathways and factors that ensure proper localization of BRCA2 and how pathogenic BRCA2 missense variants have altered localization and functionality. This knowledge will give us a better understanding of the pathogenicity of BRCA2 missense variants and how we can modulate the functionality of BRCA2. My career goal is to obtain an independent position at a leading institution where I will dissect the functionality of missense variants in DNA repair proteins and how their cellular localization is important for genome stability as a tool to predict cancer risk and to treat cancer patients. My successful transition will be supported by advancing my expertise in cell biology, biochemistry, mass spectrometry and human cellular models. I will use these acquired skills to define why and how certain pathogenic BRCA2 missense variants are mislocalized to the cytosol. Importantly, the protected time that this award provides me will allow me to elucidate the factors and pathways by which BRCA2 is transported from the cytosol to the nucleus, how this might be altered in BRCA2 missense variants and how this could be used for targeted therapies. Furthermore, the success of this project will be greatly enhanced by the outstanding advisors and collaborators that advise me through the K22 period. The receipt of this award will allow me to expand my research plan and establish myself as a principal investigator in the field of cancer biology.

项目概要/摘要 BRCA2 作为 DNA 修复途径的一部分，是同源定向修复 (HDR) 和分叉保护的关键调节因子 机制，确保基因组的稳定性。为了充分发挥活性，BRCA2 必须转运到细胞核中进行修复 DNA 双链断裂 (DSB)。在正常细胞中，核 BRCA2 缺失可能导致基因组不稳定和癌症 但是，在肿瘤细胞中，BRCA2 胞质错误定位可能导致对靶向治疗的敏感性。 我发现 BRCA2 核输入和治疗之间存在矛盾的关系。致病性错义突变 BRCA2 的 DNA 结合域将蛋白质引导至胞质溶胶，从而增加对 PARP 抑制剂的敏感性 （PARPi）和铂类药物。因此，尽管 BRCA2 错误定位可能是癌症的一个原因，但仍应保留它 脱离细胞核可以取得更好的治疗效果。这为我开辟了一条研究途径 与学习完美契合。在这个 K22 提案中，我将讨论 BRCA2 的核运输，癌症驱动因素如何 突变导致细胞质错误定位以及 BRCA2 定位如何用作诊断工具。为了测试这一点，我 将定义调节 BRCA2 致病性错义核/细胞质穿梭的分子机制 变体（目标 1），确定 BRCA2 细胞定位对 HDR、分叉保护和胞质过程的影响 （目标 2）并利用 BRCA2 定位作为癌症诊断工具（目标 3）。我的首要任务是关注错义 在我的博士后生涯中发现的变异，以破译核/胞质的潜在分子机制 BRCA2 贩运。在成功完成这项 K22 提案后，我将揭示新的途径和因素，以确保 BRCA2 的正确定位以及致病性 BRCA2 错义变异如何改变定位和功能。 这些知识将使我们更好地了解 BRCA2 错义变异的致病性以及我们如何能够 调节 BRCA2 的功能。 我的职业目标是在领先机构获得独立职位，在那里我将剖析 DNA 修复蛋白中的错义变异及其细胞定位对于基因组稳定性的重要性 预测癌症风险并治疗癌症患者。我的成功过渡将通过提高我的专业知识来支持 细胞生物学、生物化学、质谱和人类细胞模型。我将使用这些获得的技能来定义原因 以及某些致病性 BRCA2 错义变异如何错误定位到细胞质中。重要的是，受保护的时间 该奖项为我提供的帮助将让我能够阐明 BRCA2 转运的因素和途径 细胞质到细胞核，如何在 BRCA2 错义变异中改变这一点，以及如何将其用于 靶向治疗。此外，优秀的顾问和专家将极大地促进该项目的成功。 在 K22 时期为我提供建议的合作者。获得这个奖项将使我能够扩展我的研究计划 并将自己确立为癌症生物学领域的首席研究员。