The ALK receptor tyrosine kinase as a therapeutic target in neuroblastoma

描述（由申请人提供）：尽管在过去几十年中对治疗进行了重大修改，但患有晚期神经母细胞瘤（交感神经系统肿瘤）的儿童的长期治愈率仍然远远不能令人满意。我们最近在原发性神经母细胞瘤中发现了ALK受体酪氨酸激酶基因的激活体细胞突变。发现携带ALK突变的神经母细胞瘤细胞的存活依赖于突变的ALK，并且对小分子化合物的抑制非常敏感。这一提议的核心假设是，ALK在被某些突变激活时，可以维持神经母细胞瘤细胞的生长和存活，因此可以为高危神经母细胞瘤患者提供一种新的“可药用”靶标。申请人是一名新研究者，将通过解决验证潜在药物靶点、识别增强ALK抑制作用的次要靶点以及开发预防或预防耐药性的方法的关键问题来检验这一假设。这些研究将使用体外和体内模型。目的1检验ALK突变可以是乘客或驱动者的预测，只有导致激酶激活的驱动者对药理学抑制敏感。它还试图识别在ALK驱动的神经母细胞瘤细胞中具有强效活性的新型高选择性ALK激酶抑制剂。目的2将寻求初步证据，证明PI 3 K/PTEN/AKT和RAS/ERK通路是突变型ALK触发的主要下游信号通路，并且这些通路与ALK的联合抑制将增强针对神经母细胞瘤细胞的靶向治疗的细胞毒性。目的3测试ALK驱动的NB细胞中是否出现对ALK激酶抑制剂的耐药性，因为激酶本身发生突变或基因异常激活，通过篡夺突变型ALK通常使用的信号通路诱导耐药性。该提案的长期目标是从ALK介导的转化的见解中开发新的治疗选择，这些转化可以在高危神经母细胞瘤儿童的早期试验中进行测试。 公共卫生相关性：神经母细胞瘤是儿童最常见的颅外实体瘤，也是1-4岁儿童癌症死亡的主要原因。我们最近在神经母细胞瘤肿瘤中发现了酪氨酸激酶受体ALK的关键突变，为靶向治疗提供了新的焦点。该提案旨在进一步表征这些突变，测试针对ALK及其下游信号通路的抑制剂化合物，并破译ALK抑制剂耐药机制，最终目标是开发可能改善这种毁灭性疾病儿童生存率的药物。

DESCRIPTION (provided by applicant): Despite major modifications in therapy over the last few decades, the long-term cure rate in children with advanced neuroblastoma, a tumor of the sympathetic nervous system, is still far from satisfactory. We recently discovered activating somatic mutations in the ALK receptor tyrosine kinase gene in primary neuroblastomas. Neuroblastoma cells harboring ALK mutations were found to be dependent on mutant ALK for their survival and were exquisitely sensitive to inhibition by small molecule compounds. The central hypothesis of this proposal is that ALK, when activated by certain mutations, can sustain the growth and survival of neuroblastoma cells and thus could provide a novel "druggable" target in patients with high-risk neuroblastoma. The applicant, who is a New Investigator, will test this hypothesis by addressing key issues that are fundamental to validating a potential drug target, to identifying secondary targets to enhance the effects of ALK inhibition, and to developing methods to prevent or forestall drug resistance. Both in vitro and in vivo models will be utilized in these studies. Aim 1 tests the prediction that ALK mutations can be either passengers or drivers and that only drivers leading to kinase activation will be sensitive to pharmacological inhibition. It also seeks to identify novel, highly selective ALK kinase inhibitors with potent activity in ALK-driven neuroblastoma cells. Aim 2 will pursue preliminary evidence that the PI3K/PTEN/AKT and the RAS/ERK pathways serve as the principal downstream signaling pathways triggered by mutant ALK and that combined inhibition of these pathways, together with ALK, would enhance the cytotoxicity of targeted therapy directed to neuroblastoma cells. Aim 3 tests whether resistance to ALK kinase inhibitors emerges in ALK-driven NB cells because of mutations within the kinase itself or aberrant activation of genes that induce resistance by usurping the signaling pathways normally employed by mutant ALK. The long-term goal of this proposal is to develop novel therapeutic options from insights into ALK-mediated transformation that can be tested in early phase trials in children with high-risk neuroblastoma.! PUBLIC HEALTH RELEVANCE: Neuroblastoma is the most common extracranial solid tumor of children, and the leading cause of cancer deaths in children 1-4 years of age. We have recently discovered critical mutations in the tyrosine kinase receptor, ALK, in neuroblastoma tumors that provide a novel focus for targeted therapy. This proposal seeks to further characterize these mutations, to test inhibitor compounds directed against ALK and its downstream signaling pathways, and to decipher the mechanisms of resistance to ALK inhibitors with the ultimate goal of developing drugs that may improve the survival of children with this devastating disease.