Elucidation of a structural rationale for the binding of Myc by small molecule inhibitors

阐明小分子抑制剂结合 Myc 的结构原理

• 批准号: 10621176
• 负责人: Mihai Ioan Truica
• 金额: $ 5.52万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-05-01 至 2024-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10621176
• 关键词: Address; Affinity; Amino Acid Sequence; Amino Acids; Anabolism; Behavior; Binding; Binding Proteins; Biological Assay; Biophysics; Biotinylation; C-terminal; Cell physiology; Cells; Clinical; Co-Immunoprecipitations; Code; Coupled; Data; Degradation Pathway; Development; Disease; Drug Design; Drug Kinetics; Ensure; Entropy; Event; Free Energy; Goals; Hot Spot; Human; Hydrophobicity; In Vitro; Interferometry; Knowledge; MYC Family Protein; MYC gene; Malignant - descriptor; Malignant Neoplasms; Medical Research; Metabolism; Molecular; Molecular Conformation; Oncogenes; Phosphorylation; Phosphotransferases; Population; Proliferating; Protein Dynamics; Proteins; Proteome; Recombinant Proteins; Research; Role; Site-Directed Mutagenesis; Specificity; Spectrum Analysis; Stretching; Structure; Surface; Surface Plasmon Resonance; System; Testing; Therapeutic; Time; Work; biophysical properties; cancer type; cell transformation; driving force; drug discovery; experimental study; flexibility; glycogen synthase kinase 3 beta; inhibitor; member; monomer; mutant; preclinical study; protein degradation; protein folding; protein purification; research and development; screening; small molecule; small molecule inhibitor; targeted cancer therapy; theories; three dimensional structure; transcription factor; virtual

Project Summary Myc is a transcription factor essential for vital cellular processes such as proliferation, differentiation, metabolism and biosynthesis. As a result, it is often coopted during malignant transformation of cells and deregulated Myc expression occurs in virtually all cancer types. Given this role as a prominent oncogene, Myc is widely regarded as a high value cancer target. However, direct inhibition of Myc has been unsuccessful despite decades of research and development efforts. Myc is an intrinsically disordered protein (IDP) and therefore it lacks a unique, defined three-dimensional structure, which has made it extremely difficult to identify small molecule inhibitors based on traditional structure-based drug design paradigms. Instead, the protein has conformational flexibility and can access a large variety of different structures, which explains how it can recognize and bind a diverse assortment of protein partners dependent on cellular context. Notwithstanding the lack of any defined pockets in the Myc protein, several groups have identified small molecules that can disrupt Myc function. However, none of these inhibitors have made it to rigorous preclinical studies due to poor pharmacokinetic profiles and weak potency. Furthermore, there have been little to no studies demonstrating target engagement by small molecule probes of Myc in cells. This work is addressing these key barriers to progress. Small molecule binding to intrinsically disordered proteins is governed by different biophysical driving forces compared to binding of small molecules to globular, folded proteins. Binding to IDPs causes a shift in the population of available conformations and the resulting increase in entropy is the main driver of the free energy of binding. However, binding events only occur within regions on IDPs which are less disordered and more hydrophobic, providing for key, despite being relatively weak, enthalpic interactions that ensure specificity of binding. I hypothesize that Myc possesses a sequence of amino acids that serves as a small molecule binding hotspot. Using a panel of Myc mutant constructs, coupled with biotinylated small molecule Myc binders, I will elucidate the role of this Myc binding hotspot in small molecule recognition. I also hypothesize that a shift in conformational space occurs as a result of binding this Myc hotspot which directly results in an increased rate of Myc protein degradation. My preliminary data suggests that small molecule binding of Myc promotes increased interaction with proteins involved in the Myc phosphorylation and degradation pathway. Therefore, I will also elucidate how binding impacts Myc protein degradation. These experiments will advance our understanding of the factors that promote binding to IDPs and how we can leverage them to progress towards the ultimate goal of identifying a suitable clinical small molecule Myc inhibitor.

项目摘要 MYC是重要的细胞过程所必需的转录因子，例如增殖，分化，代谢 和生物合成。结果，它通常在细胞的恶性转化和失控的MYC时进行配合。 表达几乎在所有癌症类型中发生。鉴于这一角色是突出的癌基因，MYC被广泛考虑 作为高价值的癌症目标。但是，尽管数十年 研发工作。 MYC是一种本质上无序的蛋白质（IDP），因此缺乏独特的， 定义的三维结构，这使得很难识别小分子抑制剂 基于传统的基于结构的药物设计范例。相反，蛋白质具有构象的柔韧性 并可以访问各种不同的结构，这解释了它如何识别和束缚多样的 蛋白质伴侣的各种取决于细胞环境。尽管缺乏任何定义的口袋 MYC蛋白，几组已经鉴定出可能破坏MYC功能的小分子。但是，没有 这些抑制剂由于药代动力学特征差而导致严格的临床前研究。 效力。此外，几乎没有研究表明小分子的目标参与 细胞中MYC的探针。这项工作正在解决这些主要进步的关键障碍。 小分子与本质上无序蛋白的结合受不同的生物物理驱动力的控制 与小分子与球状折叠蛋白的结合相比。与IDP的结合会导致移动 可用构象的种群和熵的增加是自由能的主要驱动力 结合。但是，绑定事件仅发生在IDP的区域内，这些区域较少，而更多 疏水，提供钥匙，尽管相对较弱，焓相互作用，以确保 结合。我假设MYC拥有一系列用作小分子的氨基酸 绑定热点。使用一系列Myc突变体构建体，与生物素化的小分子MYC粘合剂结合 我将阐明这种MYC结合热点在小分子识别中的作用。我还假设这是一个转变 在构象中，由于结合了这个Myc热点，这直接导致 MYC蛋白降解的速率增加。我的初步数据表明MYC的小分子结合 促进与参与MYC磷酸化和降解途径的蛋白质相互作用的增加。 因此，我还将阐明结合如何影响MYC蛋白降解。这些实验将推进 我们对促进与IDP结合的因素以及我们如何利用它们来发展的因素的理解 确定合适的临床小分子MYC抑制剂的最终目标。