Targeting DNA Ligase I in Ovarian Cancer

靶向 DNA 连接酶 I 治疗卵巢癌

基本信息

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
项目类别：
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

项目摘要

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选择性地靶向癌细胞。此外，由于癌细胞的增殖性质，癌细胞很容易受到影响。与复制相关的 DNA 损伤，并且更依赖于处理此类损伤的途径在最近的一项合作研究中，我们发现 DNA 连接酶 I (LigI)（主要的连接酶）的水平。复制叉处的冈崎片段与卵巢癌的结果和治疗耐药性相关。此外，我们发现卵巢癌细胞在同源依赖性修复（HDR）方面存在缺陷，对 LigI 抑制敏感在初步研究中，我们比较了 LIG1 缺失与化学物质的影响。在 LIG1 缺失细胞中，LigIII 的伴侣蛋白 XRCC1 和 PARP2 水平升高。与新合成的 DNA 相关，与 PARP 和 LigIII 依赖的备份途径一致加入冈崎片段并使细胞能够在没有 LigI 的情况下进行复制。 LigI 抑制剂不会导致 XRCC1 或 PARP2 水平升高，而是导致 XRCC1 或 PARP2 水平升高。 Mre11Rad50Nbs1 复合体，启动同源依赖性修复 (HDR) 的切除步骤。在目标 1 中，我们。将结合遗传、细胞生物学和生化方法来确定该机制 LigI 抑制诱导 HDR 通路，因为 HDR 缺陷发生在遗传性和散发性形式中。卵巢癌，我们已经确定 LIG1 作为卵巢癌预后和治疗耐药性的生物标志物，我们将单独检查 LigI 抑制剂的活性以及与 DNA 修复抑制剂组合的活性和/或基于我们现有的 LigI 的基因毒性化疗药物。目标 2 中的抑制剂，我们将结合分子建模和药物化学来设计和合成假定的 LigI 抑制剂，预计具有增强的效力和选择性以及假定的 LigI 抑制剂的活性将得到平行评估。使用纯化的人类 DNA 连接酶进行生化测定，以及使用基因定义的卵巢进行基于细胞的测定在目标 3 中，我们将首先检查现有和新的 LigI 抑制剂的活性。单独使用具有遗传特征的患者来源的类器官以及与 DNA 修复抑制剂组合使用随后，用于治疗卵巢癌的化疗药物将具有最高活性的组合。在小鼠卵巢异种移植模型中进行了评估，包括患者来源的异种移植物。研究将为复制相关的 PARP 依赖性和 HDR 途径提供机制见解，在 LigI 缺陷细胞中至关重要，开发改进的 LigI 抑制剂并识别特定的 DNA 改变，从而赋予对单独的 LigI 抑制剂或与 DNA 损伤剂和/或 DNA 修复抑制剂联合使用的敏感性在临床前卵巢癌模型中，为进一步开发 LigI 抑制剂作为卵巢癌的新疗法。