Interplay between low levels of GAS7 expression and MYCN overexpression and its impact on neuroblastoma metastasis

GAS7低水平表达与MYCN过表达之间的相互作用及其对神经母细胞瘤转移的影响

基本信息

批准号：
10647655
负责人：
Shizhen Zhu
金额：
$ 35.64万
依托单位：
MAYO CLINIC ROCHESTER
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-07-15 至 2025-06-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10647655
关键词：
17p 17p13.1 Acceleration Accounting Adaptor Signaling Protein Adhesions Age Months Animal Model Attenuated Binding Biochemical Bioinformatics Biological Assay Biology Bone Marrow Cell membrane Cells Cephalic Cessation of life Childhood Chromosomes Clinical Complex Complication Coupled Data Data Set Development Diagnosis Disease Dissociation Distant Doxycycline Emerging Technologies Family Fishes Frequencies GAS7 gene Gene Expression Genes Genetic Transcription Genomics Goals Growth Hematogenous Heterozygote Human Immunoprecipitation Invaded Knock-out Knowledge Link Liver Loss of Heterozygosity Luciferases MYCN gene Malignant - descriptor Malignant Neoplasms Malignant neoplasm of lung Methylation Modeling Molecular Molecular Target Mus Mutation N-Myc Protein Neoplasm Metastasis Neuroblastoma Neuronal Differentiation Non-Malignant Ocular orbit Oncogenes Outcome Pathogenesis Patients Pediatric Neoplasm Positioning Attribute Primary Neoplasm Process Promoter Regions Reporter Role Sampling Signal Transduction Site Solid Neoplasm Subgroup System Testing Therapeutic Tissues Transplantation Treatment Failure Tumor stage Western Blotting Work Zebrafish age group bone cell motility chemotherapy effective therapy gene repression genome sequencing genomic locus high risk improved in vivo innovation insight loss of function lymph nodes member metastatic process migration mouse model neoplastic cell neuroblast novel novel therapeutics overexpression patient subsets promoter protein expression single-cell RNA sequencing success tool tumor whole genome

项目摘要

Neuroblastoma (NB), the most common extracranial solid tumor in children, typically presents at diagnosis with evidence of widespread metastasis, especially in patients with amplification of the MYCN oncogene. This subgroup has a very high risk of treatment failure and death despite receiving greatly intensified chemotherapy. Attempts to improve the treatment of disseminated NB have been impeded by the lack of a detailed understanding of the multistep cellular and molecular pathogenesis of this complex form of the tumor. Thus, new mechanistic insights leading to safer and more effective treatments for metastatic NB are urgently needed. This proposal grew from whole-genome sequencing analyses of primary NB samples from 135 patients, in which we identified a novel deletion of a growth arrest-specific gene 7 (GAS7, located on chromosome 17p13.1), in a subset of patients with high-risk NB defined by MYCN amplification. Further analysis showed that low levels of GAS7 expression are associated with advanced-stage, MYCN amplification and a poor clinical outcome, while knockout of gas7 in a zebrafish model of NB with MYCN overexpression promotes hematogenous metastasis of tumor cells to sites commonly seen in patients with this disease. We also found that MYCN can bind indirectly to the GAS7 promoter region, leading to its transcriptional repression, while reduced expression of GAS7 can increase MYCN protein levels. Hence, the central hypothesis of this application is that, in addition to cases with the heterozygous deletion of 17p, over- or amplified expression of MYCN can downregulate GAS7 expression and maintain at deficient levels of this adaptor protein. This, in turn, appears to maintain MYCN protein expression at high levels, facilitating dissociation of tumor cells from the primary tumor and their subsequent dissemination. This hypothesis will be tested in three specific aims: 1) To probe the interplay between MYCN overexpression and low levels of GAS7 expression in metastatic NB, 2) To dissect the MYCN-induced cascade of downstream transcriptional and signaling changes in the context of GAS7 deficiency that lead to metastasis in high-risk NB, and 3) To assess the contribution of GAS7 deficiency to the timing of NB dissemination and the ability of GAS7 overexpression to block or attenuate MYCN-driven tumor metastasis, and to evaluate in vivo the effect of MYCN overexpression-GAS7 deficiency on NB metastasis using different murine models. The major innovation of this proposal is the use of emerging technology with a forward-looking integration of host and tumor genomics in a high-throughput animal model to dissect the interplay between low levels of GAS7 expression and MYCN overexpression in NB metastasis. The significance of this study is threefold: it will (i) shed new light on the contributions of MYCN to early NB metastasis via its effects on adhesion, motility, and invasion, (ii) clarify the mechanism(s) that underlie MYCN’s cooperation with low levels of GAS7 expression in NB metastasis, and (iii) identify promising molecular targets within metastatic signaling cascades that could be exploited therapeutically.

神经母细胞瘤 (NB) 是儿童中最常见的颅外实体瘤，诊断时通常表现为广泛转移的证据，特别是在 MYCN 癌基因扩增的患者中。尽管接受了极大强化的化疗，亚组仍有很高的治疗失败和死亡风险。由于缺乏详细的治疗方案，改善播散性 NB 治疗的尝试受到阻碍。了解这种复杂形式的肿瘤的多步细胞和分子发病机制。迫切需要新的机制见解，为转移性 NB 提供更安全、更有效的治疗。该提议源自对 135 名患者的原发性 NB 样本的全基因组测序分析，我们发现了生长停滞特异性基因 7（GAS7，位于染色体上）的新缺失 17p13.1），在由 MYCN 扩增定义的高危 NB 患者子集中。低水平的 GAS7 表达与晚期、MYCN 扩增和较差的临床结果，而在 MYCN 过表达的 NB 斑马鱼模型中敲除gas7可促进我们还发现肿瘤细胞发生血行转移，这种情况在这种疾病的患者中很常见。 MYCN 可以间接结合到 GAS7 启动子区域，导致其转录抑制，而 GAS7 表达减少可以增加 MYCN 蛋白水平，因此，这是这一点的中心假设。应用是，除了 17p 杂合缺失的情况外，过度或扩增的表达 MYCN 可以下调 GAS7 表达并维持该接头蛋白的不足水平。似乎维持高水平的 MYCN 蛋白表达，促进肿瘤细胞从原发性肿瘤及其随后的传播将在三个具体目标上进行检验：1）探究转移性 NB 中 MYCN 过表达与低水平 GAS7 表达之间的相互作用，2) 剖析 MYCN 诱导的下游转录和信号转导变化级联 GAS7 缺乏导致高危 NB 转移，以及 3) 评估 GAS7 缺乏的贡献 NB 传播的时间和 GAS7 过表达阻断或减弱 MYCN 驱动的能力肿瘤转移，并体内评估 MYCN 过表达-GAS7 缺陷对 NB 的影响使用不同的小鼠模型进行转移该提案的主要创新是使用新兴技术。在高通量动物模型中前瞻性地整合宿主和肿瘤基因组学的技术剖析 NB 转移中低水平 GAS7 表达与 MYCN 过度表达之间的相互作用。这项研究的意义有三重： (i) 为 MYCN 对早期 NB 的贡献提供新的线索通过其对粘附、运动和侵袭的影响来确定转移，(ii) 阐明其背后的机制 MYCN 与 NB 转移中低水平 GAS7 表达的合作，以及 (iii) 确定有希望的转移性信号级联中可用于治疗的分子靶标。