Targeting DNA Ligase I in Ovarian Cancer

靶向 DNA 连接酶 I 治疗卵巢癌

• 批准号: 10737536
• 负责人: Alan E Tomkinson
• 金额: $ 37.41万
• 依托单位: UNIVERSITY OF NEW MEXICO HEALTH SCIS CTR
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-06-01 至 2028-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10737536
• 关键词: Abnormal DNA Repair; Animal Model; Biochemical; Biological; Biological Assay; Biological Markers; Cancer Model; Cancer cell line; Cell Line; Cell Survival; Cells; Chemicals; Chemoresistance; Complex; Critical Pathways; DNA Damage; DNA Ligases; DNA Repair; DNA Repair Inhibition; DNA Repair Pathway; DNA Sequence Alteration; DNA biosynthesis; DNA ligase I; DNA replication fork; DNA strand break; Defect; Development; Disease; Enzymes; Excision; Excision Repair; Experimental Models; Frequencies; Future; Genes; Genetic; Genome; Goals; Grant; Human; Hypersensitivity; Incubated; Inherited; Knockout Mice; Lesion; Ligase; Link; Maintenance; Malignant Female Reproductive System Neoplasm; Malignant neoplasm of ovary; Modeling; Molecular; Molecular Medicine; Mus; Nature; Null Lymphocytes; Okazaki fragments; Organoids; Outcome; Ovarian; Pathway interactions; Patient-Focused Outcomes; Patients; Pharmaceutical Chemistry; Pharmaceutical Preparations; Platinum; Platinum Compounds; Play; Poly Adenosine Diphosphate Ribose; Poly(ADP-ribose) Polymerase Inhibitor; Poly(ADP-ribose) Polymerases; Predisposition; Prognosis; Progression-Free Survivals; Property; Proteins; Publishing; Regimen; Resistance; Resolution; Role; Single Strand Break Repair; Structure; Testing; Therapeutic; Therapeutic Uses; Work; XRCC1 gene; Xenograft Model; cancer cell; cancer therapy; chemotherapy; design; drug development; early phase clinical trial; effective therapy; efficacy evaluation; genotoxicity; human DNA; improved; improved outcome; inhibitor; insight; intraperitoneal; molecular modeling; novel; novel therapeutic intervention; novel therapeutics; nuclease; overexpression; patient derived xenograft model; pharmacologic; pre-clinical; repaired; response; screening; standard care; targeted treatment; taxane; therapeutic development

PROJECT ABSTRACT Abnormalities in genome maintenance pathways offer an opportunity to develop therapeutic approaches that selectively target cancer cells. Furthermore, because of their proliferative nature, cancer cells are susceptible to replication-associated DNA damage and more dependent upon the pathways that deal with this type of damage. In a recent collaborative study, we found that the levels of DNA ligase I (LigI), the major enzyme joining Okazaki fragments at the replication fork, correlates with outcome and therapy resistance in ovarian cancer. Further, we found that ovarian cancer cells, which have a defect in homology-dependent repair (HDR), are sensitive to LigI inhibition. In preliminary studies we compared the effects of LIG1 deletion with chemical inhibition. In LIG1 null cells, there were elevated levels of XRCC1, the partner protein of LigIII, and PARP2 associated with newly synthesized DNA, consistent with the PARP- and LigIII-dependent back-up pathway that joins Okazaki fragments and enables cells to replicated in the absence of LigI. In contrast, incubation with the LigI inhibitor did not result in increased levels of XRCC1 or PARP2. Instead, there were elevated levels of the Mre11Rad50Nbs1 complex, that initiates the resection step of homology-dependent repair (HDR). In aim 1, we will use a combination of genetic, cell biological and biochemical approaches to determine the mechanism of the HDR pathway induced by LigI inhibition. Since HDR deficiency occurs in both inherited and sporadic forms of ovarian cancer and we have identified LIG1 as a biomarker of outcome and therapy resistance in ovarian cancer, we will examine the activity of the LigI inhibitor alone and in combination with DNA repair inhibitors and/or genotoxic chemotherapeutics in genetically-defined ovarian cancer cell lines. Building upon our existing LigI inhibitors in aim 2, we will use a combination of molecular modeling and medicinal chemistry to design and synthesize putative LigI inhibitors that are predicted to have enhanced potency and selectivity as well as improved pharmacological properties. The activity of the putative LigI inhibitors will be evaluated in parallel biochemical assays with purified human DNA ligases and cell-based assays with genetically-defined ovarian cancer cell lines. In aim 3, we will first examine the activity of existing and new LigI inhibitors for activity in genetically-characterized patient-derived organoids alone and in combination with DNA repair inhibitors and chemotherapeutics used to treat ovarian cancer. Subsequently, combinations with the highest activity will evaluated in mouse xenograft models of ovarian, including patient-derived xenografts. Together, the proposed studies will provide mechanistic insights into replication-associated PARP-dependent and HDR pathways that are critical in LigI deficient cells, develop improved LigI inhibitors and identify specific DNA alterations that confer sensitivity to the LigI inhibitor alone or in combination with DNA damaging agents and/or DNA repair inhibitors in preclinical ovarian cancer models, providing the rationale for the further development of LigI inhibitors as a novel therapeutic for ovarian cancer.

项目摘要 基因组维持途径的异常为开发治疗方法提供了机会 有选择地靶向癌细胞。此外，由于其增殖性质，癌细胞易感 与复制相关的DNA损伤，并更依赖于这种类型的途径 损害。在最近的一项合作研究中，我们发现DNA连接酶I（LIGI）的水平是主要的酶。 复制叉处的冈崎碎片与卵巢癌的结局和耐药性相关。 此外，我们发现具有同源性修复缺陷（HDR）缺陷的卵巢癌细胞是 对LIGI抑制敏感。在初步研究中，我们将Lig1缺失的影响与化学作用进行了比较 在LIG1无效细胞中，XRCC1水平升高，Ligiii和PARP2的伴侣蛋白 与新合成的DNA相关，与PARP和LIGII相关的备用途径一致 加入Okazaki碎片，并使细胞在没有Ligi的情况下复制。相反，与 LIGI抑制剂不会导致XRCC1或PARP2的水平升高。相反，有升高的水平 MRE11RAD50NBS1复合物，启动了同源依赖性修复的切除步骤（HDR）。在AIM 1中，我们 将结合遗传，细胞生物学和生化方法来确定 LIGI抑制引起的HDR途径。由于HDR缺乏症都以继承和零星形式发生 卵巢癌，我们已经确定LIG1是卵巢癌预后和耐药性的生物标志物， 我们将单独检查LIGI抑制剂的活性，并结合DNA修复抑制剂和/或 一般定义的卵巢癌细胞系中的遗传毒性化学治疗剂。建立我们现有的ligi AIM 2中的抑制剂，我们将使用分子建模和医学化学的组合来设计和 综合假定的LIGI抑制剂，预计具有提高的效力和选择性 改进的药物特性。假定的LIGI抑制剂的活性将平行评估 具有纯化的人DNA连接酶和基于细胞的卵巢的生化测定 癌细胞系。在AIM 3中，我们将首先研究现有和新的LIGI抑制剂的活动 单独使用遗传特征的患者衍生的器官，并与DNA修复抑制剂和 用于治疗卵巢癌的化学治疗剂。随后，与活动最高的组合将 在卵巢的小鼠色谱模型中进行了评估，包括患者衍生的Xenographictics。一起，提议 研究将为与复制相关的PARP依赖性和HDR途径提供机械洞察，这些途径 在Ligi缺乏细胞中至关重要，会产生改善的LIGI抑制剂，并确定会议的特定DNA改变 单独或与DNA损伤剂和/或DNA修复抑制剂组合对LIGI抑制剂的敏感性 在临床前卵巢癌模型中，为进一步开发LIGI抑制剂提供了理由 卵巢癌的新疗法。