Alternate telomere maintenance mechanisms in high-risk neuroblastoma as prognostic indicators and therapeutic targets

高危神经母细胞瘤的替代端粒维持机制作为预后指标和治疗靶点

基本信息

批准号：
10225312
负责人：
CHARLES Patrick REYNOLDS
金额：
$ 35万
依托单位：
TEXAS TECH UNIVERSITY HEALTH SCIS CENTER
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-08-29 至 2023-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10225312
关键词：
ATM activation ATRX gene Automobile Driving Behavior Biological Assay Biological Markers Cancer Cell Growth Cause of Death Cell Line Cell Nucleus Cells Chemotherapy and/or radiation Chromosomes Classification Clinical Clinical Trials Code Collaborations Complex DNA DNA Damage DNA Markers DNA Repair DNA Repair Gene DNA Repair Pathway DNA Sequence Data Disease Disease Progression Drug resistance Functional disorder Future Gene Expression Gene Expression Profile Genes Genetic Transcription Genome Stability Genomics Genotype Length Link MYCN gene Malignant Childhood Neoplasm Malignant Neoplasms Mental Retardation Molecular Molecular Target Multi-Drug Resistance Mutate Mutation Neuroblastoma Nucleoproteins Outcome Patients Pediatric Oncology Group Phenotype Phosphorylation Plasma Pre-Clinical Model Primary Neoplasm Prognosis Prognostic Marker Proliferating Proteins RNA RNA-Directed DNA Polymerase Refractory Resistance Risk Role Sampling Subgroup TERC gene TERT gene TP53 gene Telomerase Telomere Maintenance Up-Regulation alpha-Thalassemia ataxia telangiectasia mutated protein base cancer cell cancer type chemotherapy disorder risk genome-wide high risk inhibitor/antagonist kinase inhibitor knock-down mRNA Expression molecular targeted therapies multimodality neuroblastoma cell new therapeutic target nondeletion type alpha-thalassemia/mental retardation syndrome novel novel marker novel therapeutics overexpression p53-binding protein 1 patient derived xenograft model prospective small hairpin RNA small molecule small molecule inhibitor telomere therapeutic target transcriptome sequencing tumor tumor progression tumorigenic

项目摘要

ABSTRACT Clinical behavior of the childhood cancer neuroblastoma (NB) extends from spontaneous regression of untreated metastatic disease to relentless tumor progression causing death in spite of multi-modality intensive therapy. Novel therapies are needed as ~50% of high-risk NB patients die from disease. Telomeres are nucleoprotein complexes at eukaryotic chromosome ends that are essential for genomic stability by protecting the terminal regions of chromosomes from erosion of coding DNA sequences. Cancer cells require a telomere maintenance mechanism (TMM) and most activate telomerase, a ribonuclear protein containing a reverse- transcriptase encoded by the TERT gene and an RNA template encoded by the TERC gene. Some cancers are telomerase negative and employ a poorly understood alternate lengthening of telomeres (ALT) mechanism; extra-chromosomal telomeric DNA c-circles are a marker of ALT. Neuroblastomas that manifest ALT often have mutations in the alpha thalassemia/mental retardation x-linked (ATRX) gene. We established a panel of NB cell lines and patient-derived xenografts (PDXs) that manifest ALT and our preliminary data indicate that ALT can exist independent of ATRX mutations and that ALT is associated with multi-drug resistance and with increased expression of DNA repair genes. In collaboration with the Children's Oncology Group (COG) we demonstrated that high TERT mRNA expression was associated with risk of disease progression in low-risk neuroblastomas. We will classify high-risk NB by telomere maintenance mechanisms (TMM) by assessing telomerase expression, telomere content, and c-circles, and relate these in primary high- risk neuroblastomas to ATRX mutations, clinical outcome, and gene expression signatures identified by RNA sequencing. We will confirm our preliminary data indicating that ATM kinase is activated in ALT NB, serves as a driver of ALT, and stimulates overexpression of genes involved in DNA repair, promoting resistance to chemotherapy and radiation. These data will enable classification by TMM of high-risk NB into TERT-high, ALT (TERT-low, c-circle +), and an ever-shorter telomere (EST) phenotype (TERT-low and c-circle negative) and will enable determining the relationship of TMM to clinical outcome. We will knock-down, inhibit, or over-express ATM kinase in NB cell lines (ALT and non-ALT) to demonstrate its role in TMM and in the ALT phenotype, in driving expression of DNA repair genes, and in resistance to chemotherapy and radiation. Using shRNA and an ATM kinase inhibitor we will demonstrate in ALT NB cell lines and PDXs that ATM kinase is molecular therapeutic target in ALT neuroblastomas. This project employs the largest panel of ALT cell lines and PDXs established for any cancer type and will define novel biomarkers and therapeutic targets for neuroblastoma.

抽象的儿童癌症神经母细胞瘤 (NB) 的临床行为源自神经母细胞瘤的自发消退尽管进行了多模式强化治疗，未经治疗的转移性疾病仍会导致持续的肿瘤进展，导致死亡治疗。由于约 50% 的高危 NB 患者死于疾病，因此需要新的疗法。端粒是真核染色体末端的核蛋白复合物通过保护基因组稳定性至关重要染色体末端区域免受编码 DNA 序列侵蚀。癌细胞需要端粒维持机制（TMM）和大多数激活端粒酶，一种含有反向的核糖核蛋白 TERT基因编码的转录酶和TERC基因编码的RNA模板。一些癌症端粒酶呈阴性，并且采用了人们知之甚少的端粒交替延长 (ALT) 机制;染色体外端粒 DNA c 环是 ALT 的标记。神经母细胞瘤表现 ALT 通常在 α 地中海贫血/X 连锁精神发育迟滞 (ATRX) 基因中发生突变。我们成立了一组表现出 ALT 的 NB 细胞系和患者来源的异种移植物 (PDX) 和我们的初步数据表明 ALT 可以独立于 ATRX 突变而存在，并且 ALT 与多种药物相关抗性和 DNA 修复基因表达增加。与儿童肿瘤科合作组 (COG) 我们证明高 TERT mRNA 表达与疾病风险相关低风险神经母细胞瘤的进展。我们将按照端粒维持机制对高危NB进行分类 (TMM) 通过评估端粒酶表达、端粒含量和 c 环，并将这些与初级高 ATRX 突变、临床结果和 RNA 鉴定的基因表达特征的神经母细胞瘤风险测序。我们将确认我们的初步数据表明 ATM 激酶在 ALT NB 中被激活，作为 ALT 的驱动因素，并刺激参与 DNA 修复的基因过度表达，促进耐药性化疗和放疗。这些数据将使 TMM 将高风险 NB 分类为 TERT-高、ALT （TERT-低，c-环+），以及越来越短的端粒（EST）表型（TERT-低和c-环阴性），并将能够确定 TMM 与临床结果的关系。我们将敲低、抑制或过度表达 NB 细胞系（ALT 和非 ALT）中的 ATM 激酶证明其在 TMM 和 ALT 表型中的作用，驱动 DNA 修复基因的表达，并抵抗化疗和放疗。使用 shRNA 和 ATM 激酶抑制剂，我们将在 ALT NB 细胞系和 PDX 中证明 ATM 激酶是分子抑制剂 ALT 神经母细胞瘤的治疗靶点。该项目采用了最大的 ALT 细胞系和 PDX 组为任何癌症类型建立，并将定义神经母细胞瘤的新生物标志物和治疗靶点。