Discovery and optimization of novel mutant-selective allosteric inhibitors of EGFR T790M

 描述（由申请方提供）：EGFR激酶结构域突变是非小细胞肺癌的主要原因，EGFR定向酪氨酸激酶抑制剂（TKI）治疗是晚期EGFR突变型肺癌患者的标准治疗。然而，耐药性限制了这些药物的长期功效。了解和克服对EGFR TKI和其他靶向治疗的获得性耐药性是癌症医学的核心问题。与“三联鸡尾酒”疗法克服HIV病毒的致突变性库的能力类似，我们推断同时使用多种靶向突变型EGFR的药物治疗可能会防止耐药突变的出现，从而导致更持久的反应。然而，目前还没有具有替代作用机制的合适化合物。与绝大多数TKI一样，目前所有EGFR TKI均靶向激酶的ATP位点。正如我们的初步结果所述，我们正在开发新的变构EGFR抑制剂，靶向激酶中的一个独特的口袋。酶动力学研究和共晶结构证实了它们的变构作用机制。这些药物有效抑制EGFR T790 M突变体，但对野生型EGFR无活性。这些变构抑制剂的不同作用机制和结合位点，以及它们对WT EGFR和其他蛋白激酶缺乏活性，使得它们作为联合治疗的候选物特别有吸引力。我们是一个高度合作的多学科研究团队，对EGFR突变型肺癌有着浓厚的兴趣，并有成功发现抑制剂的记录。我们的专业知识涵盖激酶结构和机制（Eck，Co-PI），药物化学（Gray，Co-PI），细胞药理学（Jänne）和小鼠模型（Wong）。我们的目标是在EGFR突变型肺癌的细胞和小鼠模型中开发具有单药活性的同类第一种多药选择性变构EGFR抑制剂。为了实现这一目标，我们进一步探测变构口袋的结合库，其中虚拟配体发现与生物化学和细胞抑制测定相结合（Aim 1）。我们应用这些工具和发现，通过集中的药物化学努力来推动这些变构抑制剂的优化（目标2），并且我们使用EGFR突变型肺癌的基因工程小鼠模型（目标3）在临床前研究中确定了我们优化的化合物的功效。这些目标的成功完成将为一类新的EGFR突变型肺癌靶向治疗提供概念证明，这些肺癌对所有现有药物都有耐药性。

 DESCRIPTION (provided by applicant): Mutations in the EGFR kinase domain are a major cause of non-small cell lung cancer, and treatment with an EGFR-directed tyrosine kinase inhibitor (TKI) is the standard of care for patients with advanced EGFR-mutant lung cancer. However, resistance limits the long-term efficacy of these drugs. Understanding and overcoming acquired resistance to EGFR TKIs and to other targeted therapies is a central problem in cancer medicine. In analogy with the ability of "triple-cocktail" therapy to overcome the mutagenic repertoire of the HIV virus, we reason that simultaneous treatment with multiple agents targeting mutant EGFR may prevent emergence of resistance mutations, leading to more durable responses. However, at present suitable compounds with alternative mechanisms of action are not available. Like the vast majority of TKIs, all current EGFR TKIs target the ATP-site of the kinase. As described in our preliminary results, we are developing novel allosteric EGFR inhibitors that target a distinct pocket in the kinase. Enzyme kinetic studies and a co-crystal structure confirm their allosteric mechanism of action. These agents potently inhibit the EGFR T790M mutant, but are inactive on wild type EGFR. The distinct mechanism of action and binding site of these allosteric inhibitors, together with their lack of activity on WT EGFR and other protein kinases makes them especially attractive as candidates for combination therapy. We are a highly collaborative, multidisciplinary research team with deep interest in EGFR-mutant lung cancer and a record of successful inhibitor discovery. Our expertise spans kinase structure and mechanism (Eck, Co-PI), medicinal chemistry (Gray, Co-PI), cellular pharmacology (Jänne) and mouse models (Wong). Our goal is to develop first-in-class mutant-selective, allosteric EGFR inhibitors with single- agent activity in cellular and mouse models of EGFR-mutant lung cancer. In order to accomplish this goal, we further probe the binding repertoire of the allosteric pocket with virtual ligand discovery coupled with biochemical and cellular inhibition assays (Aim 1). We apply these tools and findings to drive optimization of these allosteric inhibitors through a focused medicinal chemistry effort (Aim 2), and we establish the efficacy of our optimized compounds in preclinical studies using genetically engineered mouse models of EGFR mutant lung cancer (Aim 3). Successful completion of these aims will provide proof of concept for a new class of targeted therapeutics for EGFR-mutant lung cancers that are resistant to all current agents.