RAD51 inhibitors for chemotherapy and radiation therapy

用于化疗和放疗的 RAD51 抑制剂

• 批准号: 8045470
• 负责人: Philip P Connell
• 金额: $ 43.45万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-03-16 至 2015-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8045470
• 关键词: Affect; Affinity; Binding; Biochemical; Biological Assay; Cancer Patient; Cancer cell line; Cells; Chemicals; Chicago; Cisplatin; DNA Damage; DNA Repair; DNA Repair Pathway; Development; Excretory function; Filament; Funding; Genetic Recombination; Goals; Human; Illinois; In Vitro; Ionizing radiation; Lead; Libraries; Malignant Neoplasms; Maximum Tolerated Dose; Measures; Mediating; Metabolism; Modification; Mus; Mutagenesis; Normal Cell; Pharmaceutical Chemistry; Pharmaceutical Preparations; Preclinical Drug Evaluation; Property; Proteins; Rad51 recombinase; Radiation; Radiation therapy; Research; Resistance; Risk; Screening procedure; Specificity; Structure; System; Techniques; Testing; Text; Therapeutic Index; Titrations; Toxic effect; Toxicity Tests; Treatment Efficacy; Universities; Work; absorption; base; cancer cell; cancer therapy; chemotherapeutic agent; chemotherapy; crosslink; improved; in vivo; inhibitor/antagonist; mouse model; novel; oncology; public health relevance; small molecule; therapeutic target; tumor; tumor xenograft

DESCRIPTION (provided by applicant): A central hypothesis of this project is that elevated levels of homologous recombinational (HR) DNA repair cause human tumors to be resistant to certain chemotherapies and radiotherapy, and that specific inhibition of HR may help overcome this resistance. Our on-going research plan involves a multistep screen for identifying small molecule inhibitors of human RAD51, which is the central protein involved in HR. An initial developmental portion of this project (funded by 1R21CA124557-01A1) has identified several lead compounds that block RAD51 filament formation, inhibit RAD51-mediated recombination in a purified system, and reduce HR in cells. This work also successfully validated RAD51 as a target for cancer therapy, and it facilitated optimization of assay techniques. The current proposal builds on this work in several ways including the support of medicinal chemistry, HR-specific cell-based assays, and in-vivo testing in a mouse model. The goal is to generate pharmacologic agents capable of sensitizing human tumors to common oncologic therapies. In Aim 1, we propose to screen a library of 6800 very pharmacologically favorable compounds, using improved assay substrates and conditions. Titrations of hit compounds will identify those with highest activities, which will be determined based on their ability to inhibit RAD51 filament formation and based on their binding affinity to RAD51 protein. In Aim 2, lead compounds will be tested for the ability to inhibit various aspects of HR in a purified system in-vitro system. The most active compounds in these biochemical assays will advance to cell-based assays, to determine which can specifically inhibit in-vivo HR at low concentrations while not affecting other DNA repair pathways. Active compounds will subsequently be tested for the ability to sensitize cancer cells to cross-linking chemotherapeutic drugs and/or ionizing radiation (IR). These cell-based assays will be performed on both cancer cell lines and non-immortalized normal cells, to identify which exert tumor-specific effects. In Aim 3 (which will be performed at UIC), the chemical sub-structures of lead compounds from earlier aims and from existing lead compounds will be optimized. Chemically-related compounds that are commercially available will first be tested. The highest priority candidate compounds will be optimized via targeted chemical modifications aimed at improving both RAD51-inhibitory activity and pharmacologic properties. ADMET (absorption, distribution, metabolism, excretion, and toxicity) properties will be measured for the most promising candidates. In Aim 4, we will test the highest priority candidate compounds candidate compounds further in a mouse model. First, the maximal tolerated dose (MTD) of compounds will be determined in mice. Second, compounds will be tested for the ability to sensitize human tumor xenografts to treatment with cisplatin or radiation. PUBLIC HEALTH RELEVANCE: Compounds are being developed to specifically sensitize cancer cells to DNA damaging therapies, particularly to radiation and chemotherapeutic agents that introduce inter-strand cross links. Our long-term goal is to generate novel pharmacologic compounds that can improve the therapeutic index of these common oncology treatments. Given that our therapeutic target (RAD51) is over-expressed in such a wide range of malignancies, this approach could potentially improve treatment efficacy for a very large group of cancer patients.

描述（由申请人提供）：该项目的一个中心假设是，同源重组（HR）DNA修复水平升高会导致人类肿瘤对某些化学疗法和放射疗法具有抗性，并且对人力资源的特定抑制可能有助于克服这种抵抗。我们正在进行的研究计划涉及一个多步筛选，用于鉴定人RAD51的小分子抑制剂，这是与HR有关的中心蛋白。该项目的初始发育部分（由1R21CA124557-01A1资助）确定了几种阻断Rad51丝形成的铅化合物，抑制了纯化系统中的Rad51介导的重组，并减少细胞中的HR。这项工作还成功验证了RAD51作为癌症治疗的靶标，并促进了测定技术的优化。当前的提案以多种方式建立在这项工作的基础上，包括在小鼠模型中支持药物化学，基于HR特异性细胞的测定和体内测试。目的是生成能够使人类肿瘤对常见肿瘤疗法敏感的药理剂。在AIM 1中，我们建议使用改进的测定底物和条件来筛选6800个非常有利的化合物的库。滴定化合物的滴定将确定具有最高活性的滴定，这将根据抑制RAD51丝形成并基于其与Rad51蛋白的结合亲和力确定。在AIM 2中，将测试铅化合物的能力，以抑制纯化系统中HR的各个方面。这些生化测定中最活跃的化合物将推向基于细胞的测定，以确定哪些可以在低浓度下特异性抑制体内HR，而不会影响其他DNA修复途径。随后，将测试活性化合物的能力，使癌细胞交联化学治疗药物和/或电离辐射（IR）的能力。这些基于细胞的测定法将在癌细胞系和非延育正常细胞上进行，以识别哪些发挥肿瘤特异性作用。在AIM 3（将在UIC执行）中，将优化来自早期目标和现有铅化合物的铅化合物的化学子结构。将首先测试与市售的化学相关化合物。最高优先级候选化合物将通过旨在改善RAD51抑制活性和药理特性的靶向化学修饰进行优化。将对最有前途的候选人测量ADMET（吸收，分布，代谢，排泄和毒性）特性。在AIM 4中，我们将在鼠标模型中进一步测试最高优先级候选化合物候选化合物。首先，将在小鼠中确定化合物的最大耐受剂量（MTD）。其次，将测试化合物的能力，以使人类肿瘤异种移植物对顺铂或辐射治疗。 公共卫生相关性：正在开发化合物，以特别使癌细胞对DNA损害疗法敏感，尤其是对引入链间交叉链路的辐射和化学治疗剂。我们的长期目标是生成新型的药理学化合物，以改善这些常见肿瘤治疗的治疗指数。鉴于我们的治疗靶标（RAD51）在如此广泛的恶性肿瘤中过表达，因此这种方法可能会提高大量癌症患者的治疗功效。