Targeting Oncogenic ALK Signaling in Neuroblastoma

描述(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方法的时代，人们正在做出巨大的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，而躯体获得性突变和扩增事件经常推动散发性肿瘤亚群的恶性过程。这就是这个项目第一阶段的动机，在那里我们证明了常见的ALK突变导致了不同的激酶激活和对ATP竞争性抑制剂的不同敏感性。这项工作确立了ALK作为NB的易处理分子靶点，并导致了目前已完成的儿科1期试验和正在进行的Crizotinib的2期试验，Crizotinib是FDA批准的唯一ALK抑制剂。我们R01的前4年的结果显示了NB中ALK激活的复杂性，并表明抑制突变的激酶结构域比淋巴瘤和肺癌中存在的融合蛋白更具挑战性。这为这项研究计划的长期目标提供了动力，即开发旨在有效抑制ALK介导的信号转导的新治疗策略。主要目的是为新诊断的ALK突变NB患者的治疗分层建立一个应答者假说，阐明对Crizotinib耐药的机制，并确定临床上的规避策略。这里要探讨的中心假设是，只有在阐明了在患者中发现的ALK变化的临床意义和驱动内在抵抗的机制之后，才能成功地开发出合理有效的ALK抑制策略。其动机是迫切需要提高高危NB的存活率，降低与治疗相关的发病率。我们将在三个具体目标中检验我们的中心假设：1)确定患者来源的ALK改变的功能后果；2)确定对ALK抑制的敏感性和抵抗力的机制；以及3)开发针对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，显示了ALK激活的各种替代遗传机制，将在复发的NB基因组中发现努力，将序列变异与致癌潜力关联起来，并优先选择下一代ALK抑制剂进行临床前和临床测试。目的2致力于阐明对克里佐替尼的内在耐药机制，这将允许合理预测联合治疗以进行进一步评估。最终目标将是 获得将联合疗法转移到诊所所需的临床前合理性， 根据我们广泛的初步数据，在克里佐替尼耐药模型中的协同药物相互作用。我们认为这个项目意义重大，因为它将导致识别NB细胞中的关键致癌易损性，将被整合到第一阶段试验中的反应和耐药的生物标记物，以及证明替代ALK抑制策略合理所需的概念验证 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.