Novel DNA Repair Inhibitors for Cancer Therapy

用于癌症治疗的新型 DNA 修复抑制剂

• 批准号: 10456727
• 负责人: PETER M GLAZER
• 金额: $ 98.49万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10456727
• 关键词: Affinity; Animals; Anti-Idiotype Vaccine; Antibodies; Autoantibodies; BRCA2 gene; Binding; Biological Markers; Cancer cell line; Cell membrane; Cells; Chemotherapy and/or radiation; Clinic; DNA; DNA Damage; DNA Repair; DNA Repair Pathway; DNA-dependent protein kinase; Development; Dropout; Glioma; Human; Isocitrate Dehydrogenase; Lupus; Malignant Neoplasms; Mus; Mutation; Nature; Nonhomologous DNA End Joining; Normal tissue morphology; PTEN gene; Pathway interactions; Patients; Penetration; Peptides; Phase I Clinical Trials; Phenotype; Positioning Attribute; Publishing; RNA; Radiation; Testing; Therapeutic; Therapeutic Agents; Toxic effect; Tumor Tissue; Work; base; cancer cell; cancer therapy; chemotherapy; in vivo; inhibitor; leukemia; neoplastic cell; next generation; novel; novel therapeutics; pre-clinical; repaired; response; small hairpin RNA; small molecule; synergism; tumor; tumor microenvironment

Project Summary/Abstract. We seek to identify novel therapeutic agents that are selectively toxic to cancer cells and that specifically sensitize tumors to radiation or chemotherapy. We have discovered that a cell-penetrating, lupus-derived autoantibody (3E10) increases the sensitivity of cancer cells to radiation and to DNA-targeted chemotherapy. Importantly, 3E10, by itself, is synthetically lethal to BRCA2- and PTEN-deficient cancer cells, but is otherwise non-toxic to cells in culture or to mice. The antibody also showed no detectable toxicity in humans when tested in a phase I clinical trial in lupus patients as a putative anti-idiotype vaccine. We previously determined 3E10 to be a potent inhibitor of homology-dependent repair (HDR), and we have now identified RAD51 as the functional target. We have also found that 3E10 is preferentially taken up in tumor tissue in vivo based on its mechanism of cell penetration, providing a further basis to pursue its development for cancer therapy. These new results provide the basis to enhance the potency of 3E10 (by directed mutation, affinity maturation, and multi-valent constructs) and to rationally develop therapeutic strategies by identifying synthetic lethal interactions (via unbiased shRNA dropout screen and interrogation of curated cancer cell lines) and determining synergies with other agents, as a prelude to pre-clinical animal tumor studies. We expect that 3E10 will be synthetic lethal to cancers deficient in DNA repair and damage response pathways. We also have developed a strategy to selectively target DNA repair inhibitors to tumors by exploiting the acidic tumor microenvironment. We will use a pH low insertion peptide (pHLIP) that inserts directionally across cell membranes at low pH and delivers cargoes selectively into tumor cells in vivo. Focusing on DNA-PK in the non-homologous end-joining pathway (NHEJ) of DNA repair, we will build on advances made in collaborative work to develop tumor-targeted antisense and small molecule inhibition of DNA-PK. We will incorporate next generation γPNAs modified at the γ position to increase binding to RNA for potent antisense activity. This is based on our promising proof-of-concept studies published in Nature demonstrating the in vivo anti-tumor activity of pHLIP-PNA conjugates. We will also conjugate small molecule DNA-PK inhibitors to pHLIP, leveraging potent molecules that have not advanced to the clinic because of normal tissue toxicity, and conferring tumor selectivity. This work will provide a versatile platform to apply to other DNA repair targets. We have recently identified the oncometabolite, 2-hydroxyglutarate (2HG), as a new biomarker of deficient DNA repair in human malignancies. We found that elevated levels of 2HG confer a BRCAness phenotype of deficient HDR that renders cancer cells sensitive to synthetic lethal killing by PARP inhibitors and by 3E10. 2HG is produced by the neomorphic activity of isocitrate dehydrogenase-1 and -2 (IDH1/2) mutations found in gliomas, leukemia, and other cancers. We will investigate the mechanism by which 2HG suppresses DNA repair and identify vulnerabilities that can be exploited for therapeutic gain in human tumors.

项目摘要/摘要。 我们寻求识别对癌细胞具有选择性毒性的新型治疗剂，并且特别是 使肿瘤对放射或化疗敏感。我们发现一种源自狼疮的细胞穿透性 自身抗体 (3E10) 增加癌细胞对放射线和 DNA 靶向化疗的敏感性。 重要的是，3E10 本身对 BRCA2 和 PTEN 缺陷的癌细胞具有综合致死性，但除此之外 对培养细胞或小鼠无毒。测试时，该抗体对人体也没有显示出可检测到的毒性 作为假定的抗独特型疫苗，在狼疮患者中进行了 I 期临床试验。我们之前确定 3E10 为 是同源依赖性修复 (HDR) 的有效抑制剂，我们现在已将 RAD51 确定为 功能目标。我们还发现，基于 3E10 的活性，3E10 在体内优先被肿瘤组织吸收。 细胞渗透机制，为其癌症治疗的发展提供进一步的基础。这些 新结果为增强 3E10 的效力提供了基础（通过定向突变、亲和力成熟和 多价结构）并通过识别合成致死剂来合理制定治疗策略 相互作用（通过无偏见的 shRNA 丢失筛选和对精心设计的癌细胞系的询问）和 确定与其他药物的协同作用，作为临床前动物肿瘤研究的前奏。我们期望 3E10 对缺乏 DNA 修复和损伤反应途径的癌症具有合成致死作用。 我们还开发了一种策略，通过利用 DNA 修复抑制剂选择性地靶向肿瘤 酸性肿瘤微环境。我们将使用 pH 低插入肽 (pHLIP)，它可以定向插入 在低 pH 下的细胞膜上，选择性地将货物递送到体内的肿瘤细胞中。专注于DNA-PK DNA 修复的非同源末端连接途径 (NHEJ)，我们将在合作取得的进展的基础上 致力于开发肿瘤靶向反义药物和 DNA-PK 的小分子抑制药物。接下来我们将合并 生成在 γ 位进行修饰的 γPNA，以增加与 RNA 的结合，从而实现有效的反义活性。这是 基于我们在《自然》杂志上发表的有前景的概念验证研究，证明了体内抗肿瘤作用 pHLIP-PNA 缀合物的活性。我们还将小分子 DNA-PK 抑制剂与 pHLIP 结合， 利用由于正常组织毒性而尚未进入临床的有效分子，以及 赋予肿瘤选择性。这项工作将提供一个通用平台，应用于其他 DNA 修复目标。 我们最近发现了致癌代谢物 2-羟基戊二酸 (2HG)，作为维生素缺乏症的新生物标志物。 人类恶性肿瘤中的 DNA 修复。我们发现 2HG 水平升高会导致 BRCAness 表型 HDR 缺陷使癌细胞对 PARP 抑制剂和 3E10 的合成致死杀伤敏感。 2HG 是由异柠檬酸脱氢酶-1 和 -2 (IDH1/2) 突变的新形态活性产生的， 神经胶质瘤、白血病和其他癌症。我们将研究2HG抑制DNA的机制 修复和识别可用于人类肿瘤治疗效果的漏洞。