Discovery and development of Ku-targeted small molecule inhibitors: A novel mechanism of DNA-PK inhibition

Ku 靶向小分子抑制剂的发现和开发：DNA-PK 抑制的新机制

• 批准号: 10358629
• 负责人: Navnath S Gavande
• 金额: $ 57.28万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-03-13 至 2025-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10358629
• 关键词: Active Sites; Address; Advanced Development; Antineoplastic Agents; Automobile Driving; BRCA1 gene; BRCA2 gene; Binding; Biochemical; Biological Availability; Bleomycin; Cancer Model; Cells; Characteristics; Chemicals; Chemistry; Chemotherapy and/or radiation; Cisplatin; Clinical; Combined Modality Therapy; Coupled; Crystallization; DNA; DNA Binding; DNA Damage; DNA Double Strand Break; DNA Repair; DNA Sequence Alteration; DNA-PKcs; DNA-dependent protein kinase; Data; Development; Dose; Double Strand Break Repair; Drug Design; Drug Kinetics; Etoposide; Generations; Genetic; Genetic study; Genome Stability; Health; Human; In Vitro; Ionizing radiation; Knowledge; Lung; Maintenance; Malignant Neoplasms; Malignant neoplasm of lung; Malignant neoplasm of ovary; Mediating; Modeling; Modification; Molecular; Molecular Mechanisms of Action; Nonhomologous DNA End Joining; Outcome; Ovarian; Pathway interactions; Patients; Pharmaceutical Chemistry; Pharmaceutical Preparations; Pharmacology; Pharmacology Study; Phosphotransferases; Play; Property; Publishing; Radiation; Reagent; Regulation; Reporting; Research; Roentgen Rays; Role; Series; Signal Pathway; Signal Transduction; Stress; Structure; Structure-Activity Relationship; Therapeutic; Therapeutic Agents; Toxic effect; anti-cancer; anti-cancer therapeutic; base; cancer cell; cancer genetics; cancer therapy; clinically relevant; design; early phase clinical trial; genetic manipulation; homologous recombination; in vivo; inhibitor; innovation; molecular targeted therapies; nanomolar; novel; novel therapeutics; protein kinase inhibitor; recombinational repair; repaired; response; small molecule; small molecule inhibitor; targeted agent; uptake

The DNA-dependent protein kinase (DNA-PK) is a validated target for cancer therapeutics involved in the DNA-damage response (DDR) and non-homologous end joining (NHEJ) double strand break (DSB) repair pathways. Various anti-cancer therapeutic strategies, including ionizing radiation (IR) impart their efficacy by inducing DNA DSBs. Both genetic and pharmacologic studies have demonstrated that modulating the DDR and DSB repair pathways has a profound impact on the efficacy of DNA damaging therapeutic agents supporting the premise of targeting DNA-PK in cancer therapy. Development of DNA-PK inhibitors thus far has focused entirely on targeting the DNA-PKcs active site, three of which are currently in early phase clinical trials. We have exploited the requirement for DNA-PK activation of binding to DNA termini via the Ku 70/80 heterodimer to identify small molecule Ku inhibitors that inhibit DNA-PK via a novel mechanism. Preliminary data show that Ku-inhibitors abrogate DNA-PK catalytic activity at nanomolar concentrations and potentiate cellular sensitivity to DSB-inducing therapeutics. We have also proven that the observed cellular effects are a function of direct on-target Ku inhibition. Based on the rigorous published and preliminary data we hypothesize that DNA-PK inhibition mediated by targeting Ku-DNA binding, will inhibit the DDR and NHEJ pathways resulting in sensitization of cancer cells to DNA damaging anti-cancer agents. To address this hypothesis, we propose three specific aims. In Aim 1 we will develop highly potent and selective DNA-PK inhibitors by targeting the Ku-DNA interaction. Having established nanomolar inhibitors, chemistry efforts will focus on optimizing the physicochemical and pharmacokinetic properties to increase cellular uptake and bioavailability while retaining excellent potency and selectivity. In Aim 2 we will determine the molecular mechanism of action (MOA) of Ku inhibitors and elucidate how chemical inhibition of Ku impacts the cellular DDR and repair pathways. In Aim 3 we will interrogate how modulation of DSB repair via HRR and DDR signaling due to Ku inhibition impacts anticancer efficacy alone and in combination therapy in clinically relevant models of lung and ovarian cancer. We will also assess the impact of common cancer genetic mutations in genome stability and maintenance pathways (including BRCA1 and BRCA2) towards exploiting synthetic lethal interactions to enhance drug and radiation efficacy. Completion of these studies will provide essential information for the continued discovery and development of novel Ku-targeted DNA-PK inhibitors. The impact of this research thus extends beyond the generation of new knowledge, reagents and models to provide new molecularly targeted treatment options for a wide array of cancers that are currently difficult to treat effectively.

DNA 依赖性蛋白激酶 (DNA-PK) 是相关癌症治疗的经过验证的靶点 DNA 损伤反应 (DDR) 和非同源末端连接 (NHEJ) 双链断裂 (DSB) 修复通路。各种抗癌治疗策略，包括电离辐射 (IR) 都具有各自的作用 通过诱导 DNA DSB 发挥功效。遗传和药理学研究都表明，调节 DDR 和 DSB 修复途径对 DNA 损伤治疗剂的功效具有深远的影响 支持癌症治疗中靶向 DNA-PK 的前提。迄今为止，DNA-PK抑制剂的开发已 完全专注于靶向 DNA-PKcs 活性位点，其中三个目前处于早期临床试验阶段。 我们利用了通过 Ku 70/80 结合 DNA 末端的 DNA-PK 激活的要求 异二聚体来鉴定通过新机制抑制 DNA-PK 的小分子 Ku 抑制剂。初步的 数据显示 Ku 抑制剂在纳摩尔浓度下消除 DNA-PK 催化活性并增强 细胞对 DSB 诱导疗法的敏感性。我们还证明观察到的细胞效应是 直接靶向 Ku 抑制的功能。根据严格公布的初步数据，我们 假设通过靶向 Ku-DNA 结合介导的 DNA-PK 抑制将抑制 DDR 和 NHEJ 通路导致癌细胞对 DNA 损伤性抗癌药物敏感。到 针对这一假设，我们提出了三个具体目标。在目标 1 中，我们将开发高效且有选择性的 DNA-PK 抑制剂通过靶向 Ku-DNA 相互作用。建立纳摩尔抑制剂后，化学 工作重点是优化理化和药代动力学特性，以增加细胞摄取 和生物利用度，同时保持优异的效力和选择性。在目标 2 中，我们将确定分子 Ku 抑制剂的作用机制 (MOA) 并阐明 Ku 的化学抑制如何影响细胞 DDR 和修复途径。在目标 3 中，我们将探讨如何通过 HRR 和 DDR 调制 DSB 修复 Ku 抑制引起的信号转导会影响临床相关的单独治疗和联合治疗的抗癌功效 肺癌和卵巢癌模型。我们还将评估常见癌症基因突变的影响 基因组稳定性和维护途径（包括 BRCA1 和 BRCA2），以利用合成致死性 相互作用以增强药物和放射疗效。完成这些研究将提供必要的 持续发现和开发新型 Ku 靶向 DNA-PK 抑制剂的信息。影响 因此，这项研究的范围超出了新知识、试剂和模型的产生，以提供新的 针对目前难以有效治疗的多种癌症的分子靶向治疗方案。