Targeting Oncogenic ALK Signaling in Neuroblastoma

描述（由申请人提供）：神经母细胞瘤（NB）仍然是儿童癌症死亡的主要原因。存活下来的儿童会留下长期的副作用，其中许多可能危及生命。在这个更合理的治疗时代，人们正在做出大量努力来确定最佳靶点。我们发现ALK癌基因的激活突变是遗传性NB的主要原因，并且体细胞获得性突变和扩增事件通常驱动散发性肿瘤子集的恶性过程。这是该项目第一阶段的动机，我们随后证明了常见的ALK突变导致激酶激活差异和对ATP竞争性抑制剂的敏感性差异。这项工作确立了ALK作为NB中易处理的分子靶点，并导致目前已完成的儿科I期试验和正在进行的克唑替尼II期试验，克唑替尼是唯一一种FDA批准的ALK抑制剂。R 01前4年的结果显示了NB中ALK激活的复杂性，并证明抑制突变激酶结构域比抑制淋巴瘤和肺癌中存在的融合蛋白更具挑战性。这为本研究提案的长期目标提供了动力，即开发旨在有效抑制ALK介导的信号传导的新型治疗策略。主要目的是为新诊断的ALK突变NB患者的治疗分层建立应答者假设，阐明克唑替尼耐药机制，并确定临床规避策略。这里要探讨的中心假设是，只有在阐明患者中发现的ALK改变的临床意义和驱动内在耐药的机制后，才能成功开发合理有效的ALK抑制策略。其动机是迫切需要提高高危NB的生存率和降低治疗相关的发病率。我们将在三个特定目标中检验我们的中心假设：1）定义患者源性ALK改变的功能后果; 2）确定对ALK抑制的敏感性和耐药性机制; 3）开发靶向ALK信号通路的合理治疗组合以克服耐药性。第一个目标是基于最近未发表的数据，显示ALK激活的各种替代遗传机制，将是在复发性NB基因组中的发现工作，将序列变异与致癌潜力相关联，并优先考虑下一代ALK抑制剂进行临床前和临床试验。目的2致力于阐明对克唑替尼的内在耐药机制，这将允许合理预测组合疗法以进行进一步评价。最终目标将 获得将联合治疗转移到临床所需的临床前理由， 我们在克唑替尼耐药模型中的协同药物相互作用的广泛初步数据。我们认为该项目具有重要意义，因为它将识别NB细胞中的关键致癌脆弱性，将纳入I期试验的应答和耐药生物标志物，以及证明替代ALK抑制策略合理性所需的概念验证 用于早期临床试验开发。

DESCRIPTION (provided by applicant): Neuroblastoma (NB) remains a leading cause of childhood cancer deaths. Children who do survive are left with long-term side effects, many of which can be life threatening. In this era of more rational therapies, substantial efforts are bein made to identify optimal targets. We discovered that activating mutations of the ALK oncogene are the major cause of hereditary NB, and that somatically acquired mutations and amplification events often drive the malignant process in a subset of sporadic tumors. This was the motivation for the first phase of this project, where we then demonstrated that the common ALK mutations result in differential kinase activation and differential sensitivity to ATP-competitive inhibitors. This work established ALK as a tractable molecular target in NB and led to a now completed pediatric phase 1 trial and ongoing phase 2 trial of crizotinib, the only FDA approved ALK inhibitor. The results from the first 4 years of our R01 show the complexity of ALK activation in NB, and demonstrate that inhibition of a mutant kinase domain is much more challenging than fusion proteins present in lymphomas and lung cancer. This provides the impetus for the long-term goal of this research proposal to develop novel therapeutic strategies aimed at effectively inhibiting ALK-mediated signaling. The primary objective is to develop a responder hypothesis for therapeutic stratification of newly diagnosed patients with ALK-mutant NB, to elucidate mechanisms of resistance to crizotinib, and to define circumvention strategies in the clinic. The central hypothesis to be explored here is that rational and effective ALK-inhibition strategies can only be successfully developed after elucidation of the clinical implications of ALK alterations identified in patients and the mechanisms driving intrinsic resistance. The motivation is the urgent need to improve high-risk NB survival rates and decrease treatment-related morbidities. We will test our central hypothesis in three specific aims: 1) Define the functional consequences of patient-derived ALK alterations; 2) Identify mechanisms of sensitivity and resistance to ALK inhibition; and 3) Develop rational therapeutic combinations targeting ALK signaling pathways to overcome resistance. The first Aim, based on recent unpublished data showing a variety of alternative genetic mechanisms for ALK activation, will be a discovery effort in the relapsed NB genome, correlating sequence variations with oncogenic potential and prioritizing next-generation ALK inhibitors for preclinical and clinical testing. Aim 2 is devoted to elucidate mechanisms of intrinsic resistance to crizotinib that will allow for rational prediction of combinatorial therapies for further evaluation. The final Aim will garner the preclinical justification required to move combination therapies to the clinic, building on our extensive preliminary data of synergistic drug interactions in crizotinib-resistant models. We consider this project significant because it will result in identification of key oncogenic vulnerabilities in NB cells, biomarkers of response and resistance which will be integrated into phase 1 trials, and the proof-of- concept required to justify alternative ALK inhibition strategies for early phase clinical trial development.