MYC activation in tumor progression of neuroblastoma

用13-顺式视黄酸（13-cisRA）和嵌合抗GD 2的巩固后维持疗法 抗体dinutuximab（Unituxin®）改善了高危神经母细胞瘤（NB）患者的存活率。 尽管目前有最佳治疗，但仍有> 40%的儿童出现复发性疾病， 对大多数人来说是致命的。在目前的建议中，我们试图确定进行性疾病的分子机制， NB患者。虽然在1%的NB患者中观察到MYC基因组扩增，但c-MYC蛋白在NB患者中的表达率很低。 11%的患者在诊断时过度表达。我们的初步数据显示，高c-MYC蛋白 相对于使用患者来源的细胞的诊断， 在疾病进展时和诊断时从临床样品建立的线。在搜索 MYC转录激活的机制，我们证明了转录因子，OCT 4和 TCF 3在选择表达高c-MYC的细胞系模型中升高， 高危神经母细胞瘤维持治疗（13-cisRA）的治疗方案。当OCT 4 敲低c-MYC后，c-MYC表达降低，对13-cisRA的敏感性恢复。 随后，我们鉴定了两种激酶，MAPKAPK 2（MK2）和DNAPK，它们被预测为结合 并磷酸化OCT 4。MK2-OCT 4-c-MYC轴在另一种进行性疾病中得到证实 具有高c-MYC表达的神经母细胞瘤模型。根据我们的初步数据，我们假设 1)激酶磷酸化OCT 4，磷酸化的OCT 4诱导转录激活， c-MYC，并且可以靶向这些激酶以抑制OCT 4诱导的c-MYC的活化 过表达，因此激酶的表达可以是生物标志物和治疗靶点， 伴有高c-MYC的进行性疾病患者。我们的目标是：1）利用我们广泛的小组， NB细胞系和患者来源的异种移植物（PDX）来定义OCT 4及其 在c-MYC过表达中由MK2和DNA-PKcs激酶进行的磷酸化调节表明， 导致对NB中的一种维持治疗产生耐药性，2）验证它们作为NB的潜在标志物， 与儿童肿瘤学小组（COG）合作在患者肿瘤样本中的结果较差，以及 3)证明抑制关键激酶以调节0 CT 4/c-MYC轴以增强OCT 4/c-MYC的表达的可行性。 化疗在NB细胞系和患者来源的异种移植物（PDX）中的活性。的最终目标 该研究旨在验证c-MYC的调节作为肿瘤进展的一种新机制， 本发明的目的是提供一种治疗神经母细胞瘤的方法，并鉴定耐药性复发性神经母细胞瘤的可药物靶点。

Post-consolidation maintenance therapy with 13-cis retinoic acid (13-cisRA) and the chimeric anti-GD2 antibody dinutuximab (Unituxin®) improves the survival of high-risk neuroblastoma (NB) patients. Despite currently available optimal therapy > 40% of children still develop recurrent disease, which is fatal for most. In the current proposal we seek to identify molecular mechanisms of progressive disease in NB patients. Although MYC genomic amplification is seen in 1% of NB patients, c-MYC protein is overexpressed in 11% of patients at diagnosis. Our preliminary data show that high c-MYC protein expression is far more frequent in progressive disease relative to diagnosis using patient-derived cell lines established from clinical samples at progressive disease and at diagnosis. In searching the mechanisms of MYC transcriptional activation, we demonstrated that transcription factors, OCT4 and TCF 3 were elevated in a cell line model selected to express high c-MYC in replicating the clinical treatment schedule of maintenance therapy (13-cisRA) in high-risk neuroblastoma. When OCT4 was knocked-down, the expression of c-MYC was decreased and the sensitivity to 13-cisRA was restored. Subsequently, we identified two kinases, MAPKAPK2 (MK2) and DNAPK, which are predicted to bind and phosphorylate OCT4. The MK2-OCT4-c-MYC axis was confirmed in another progressive disease model of neuroblastoma with high c-MYC expression. Based on our preliminary data, we hypothesize 1) that kinase(s) phosphorylate OCT4 and the phosphorylated OCT4-induces transcriptional activation of c-MYC and that those kinases can be targeted to inhibit the activation of OCT4-induced c-MYC overexpression, and thus the expression of the kinase(s) could be biomarkers and therapeutic targets for patients with progressive disease with high c-MYC. Our goals are: 1) to employ our extensive panel of NB cell lines and patient-derived xenografts (PDXs) to define the specific roles of OCT4 and its phosphorylation regulation by MK2 and DNA-PKcs kinases in a c-MYC overexpression state that causes resistance to one of the maintenance therapy in NB, 2) to validate them as potential markers of poor outcome in collaboration with the Children's Oncology Group (COG) in patient tumor samples, and 3) to demonstrate the feasibility of inhibiting key kinase(s) to modulate OCT4/c-MYC axis to enhance activity of chemotherapy in NB cell lines and patient-derived xenografts (PDXs). The ultimate goal of the proposed study is to validate regulation of c-MYC as a novel mechanism of tumor progression in neuroblastoma and to identify a druggable target(s) for drug-resistant recurrent neuroblastoma.