MYC activation in tumor progression of neuroblastoma

13-顺式维甲酸(13-Cisra)和嵌合抗GD2的巩固后维持治疗 迪努西单抗(Unitusin®)抗体可提高高危神经母细胞瘤(NB)患者的存活率。 尽管目前有最佳的治疗方法，但仍有40%的儿童患上复发性疾病。 对大多数人来说都是致命的。在目前的提案中，我们试图确定进行性疾病的分子机制。 在NB患者中。虽然在1%的NB患者中可以看到MYC基因组扩增，但c-MYC蛋白是 在确诊时，11%的患者过表达。我们的初步数据显示，高c-myc蛋白 与使用患者来源的细胞进行诊断相比，进展性疾病中的表达更频繁 从进展性疾病和确诊时的临床样本建立的系。在搜索 MYC转录激活的机制，我们证明了转录因子OCT4和OCT4 在复制临床病例中，在选择表达高c-myc的细胞系模型中，tcf3水平升高。 高危神经母细胞瘤维持治疗方案(13-Cisra)。当OCT4是 C-myc表达降低，对13-cisra的敏感性恢复。 随后，我们确定了两个被预测结合的激酶，MAPKAPK2(MK2)和DNAPK 并使OCT4磷酸化。MK2-OCT4-c-myc轴在另一种进展性疾病中被证实 高表达c-myc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(S)磷酸化OCT4和磷酸化OCT4-诱导转录激活 C-myc和这些激酶可以靶向抑制OCT4诱导的c-myc的激活。 过表达，从而使激酶(S)的表达可能成为肿瘤的生物标志物和治疗靶点。 进展性疾病患者c-myc升高。我们的目标是：1)聘用我们广泛的 NB细胞系和患者来源的异种移植(PDX)以确定OCT4及其受体的特定作用 MK2和DNA-PKcs在c-myc过表达状态下的磷酸化调节 导致对NB中的一种维持疗法产生耐药性，2)以验证它们是否为潜在的 与儿童肿瘤学小组(COG)在患者肿瘤样本方面的合作结果不佳，以及 3)论证了抑制关键蛋白激酶(S)调控OCT4/c-myc轴增强的可行性。 化疗在NB细胞系和患者来源的异种移植(PDX)中的活性。的最终目标是 拟议的研究旨在验证c-myc作为一种新的肿瘤进展机制的调节作用。 神经母细胞瘤，并寻找耐药复发神经母细胞瘤的药物靶点(S)。

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.