Chemical Modulation of Orphan Nuclear Receptor Function

孤儿核受体功能的化学调节

• 批准号: 8266518
• 负责人: Sridhar Mani
• 金额: $ 26.73万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-13 至 2014-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8266518
• 关键词: Adopted; Affinity; Agonist; Antineoplastic Agents; Azoles; Binding; Binding Sites; Biochemical Genetics; Biological Assay; Cell Proliferation; Cells; Chemicals; Clinical; Collaborations; Complement; Complex; Computer Simulation; Coumestrol; Cytochromes; Data; Development; Drug Interactions; Drug resistance; Generations; Genetic Transcription; Goals; Grant; Hepatic; Human; Imidazole; Immune; Ketoconazole; Knowledge; Laboratories; Lead; Libraries; Ligand Binding; Ligands; Mammalian Cell; Mediating; Microsomes; Modeling; Modification; Molecular; Mus; Mutation; Nuclear; Nuclear Orphan Receptor; Nuclear Receptors; Organ; Orphan; Paclitaxel; Pharmaceutical Preparations; Phenotype; Play; Protein Binding; Proteins; Receptor Activation; Receptor Inhibition; Research Personnel; Resistance; Role; Site; Structure; Surface; System; Tamoxifen; Testing; Tissues; Toxic effect; Yeasts; abstracting; analog; base; cancer cell; cytotoxicity; glycidol; improved; inhibitor/antagonist; monolayer; mutant; novel; pharmacophore; pregnane X receptor; receptor; receptor binding; receptor function; small molecule; tool; yeast two hybrid system

Project Summary/Abstract The central goal of this R01 is to focus on explicitly defining novel antagonist binding pharmacophore on Pregnane X Receptor (PXR). In doing so, additional goals include development of non-toxic azole antagonists that would serve to chemically probe PXR activity and phenotype(s) in different tissues. In silico modeling parameters will continuously be improved as we obtain potent and specific PXR inhibitors. These models could then guide the development of novel small molecule antagonists originating from different chemical entities. The long-term goal is to eventually develop non-toxic antagonists of PXR that can be used as clinical modulators of cancer cell proliferation and drug resistance (e.g., PXR activation induces cancer cell proliferation and drug resistance). It is also hoped that these antagonists will enhance the activity, and minimize the toxicity, of select antineoplastic agents (e.g., tamoxifen, paclitaxel are PXR agonist at concentrations observed at steady-state in humans). Towards this end, we have identified and characterized two novel PXR antagonists, ketoconazole and coumestrol, that specifically disrupt the function of activated (ligand-bound) PXR. In subsequent studies, we have shown that ketoconazole: (i) binds to receptor and disrupts coregulator-receptor interactions in activated PXR; (2) does not displace activating drugs from the ligand-binding pocket of PXR; (iii) retained antagonism of mutant forms of PXR containing ligand-binding pocket filling mutants; and (iv) is unable to antagonize mutant forms of PXR containing alterations in the surface coregulator AF-2 binding site. Thus, we have formulated a model for PXR antagonism in which disruption of function is mediated either by allosteric modification of the receptor or by competition with coregulator binding. We now propose to evaluate this model using structural, molecular, biochemical, and genetic systems to characterize the mechanism by which PXR-directed antagonist ketoconazole and related compounds inhibit receptor activation.

项目概要/摘要 该 R01 的中心目标是专注于明确定义新型拮抗剂结合 孕烷 X 受体 (PXR) 上的药效团。在此过程中，其他目标包括 开发可用于化学探测 PXR 的无毒唑类拮抗剂 不同组织中的活性和表型。计算机模拟参数将 随着我们获得有效且特异的 PXR 抑制剂，我们的技术将不断得到改进。这些 然后模型可以指导新型小分子拮抗剂的开发 源自不同的化学实体。长远目标是最终发展 可用作癌细胞临床调节剂的无毒 PXR 拮抗剂 增殖和耐药性（例如，PXR 激活诱导癌细胞增殖 和耐药性）。还希望这些拮抗剂能够增强活性， 并尽量减少所选抗肿瘤药物（例如他莫昔芬、紫杉醇）的毒性 PXR 激动剂在人体稳态时观察到的浓度）。为了这个目的， 我们已经鉴定并表征了两种新型 PXR 拮抗剂：酮康唑和 香雌酚，专门破坏激活（配体结合）PXR 的功能。在 随后的研究表明，酮康唑：（i）与受体结合并破坏 激活 PXR 中的核心调节器-受体相互作用； (2)不取代活化药物 来自 PXR 的配体结合口袋； (iii)保留了PXR突变体形式的拮抗作用 含有配体结合袋填充突变体； (iv) 无法对抗突变体 含有表面共调节剂 AF-2 结合位点改变的 PXR 形式。因此， 我们制定了 PXR 拮抗模型，其中功能破坏是 通过受体的变构修饰或与受体的竞争介导 核心调节器结合。我们现在建议使用结构、分子、 生化和遗传系统来表征 PXR 引导的机制 拮抗剂酮康唑和相关化合物抑制受体激活。