Mediators Of Arrested Differentiation In Pediatric Rhabdomyosarcoma

小儿横纹肌肉瘤分化停滞的介质

• 批准号: 10331082
• 负责人: Mark Edward Hatley
• 金额: $ 40.24万
• 依托单位: ST. JUDE CHILDREN'S RESEARCH HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-02-01 至 2026-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10331082
• 关键词: AKT1 gene; Acute Promyelocytic Leukemia; Affinity Chromatography; Attenuated; Automobile Driving; Binding; Binding Sites; Biological Assay; Biology; Cell Nucleus; Cells; ChIP-seq; Child; Childhood; Childhood Brain Neoplasm; Childhood Rhabdomyosarcoma; Clinical Trials; Coupled; DNA sequencing; Deletion Mutation; Development; Differentiation Therapy; Dissection; Embryonal Rhabdomyosarcoma; Ependymoma; FOXO1A gene; FRAP1 gene; Gene Expression Profile; Gene Fusion; Genes; Genetic Engineering; Genetic Transcription; Genetically Engineered Mouse; Goals; Human; Hypermethylation; In Vitro; Isotretinoin; Knowledge; Laboratories; Life; Luciferases; MM form creatine kinase; Malignant Neoplasms; Malignant neoplasm of brain; Mass Spectrum Analysis; Mediator of activation protein; Modeling; Molecular; Mus; Muscle Development; Myoblasts; Neuroblastoma; Neurons; Nucleic Acid Regulatory Sequences; PAX3 gene; PAX7 gene; PTEN gene; Pathway interactions; Penetrance; Pharmacotherapy; Phenotype; Proteins; Proto-Oncogene Proteins c-akt; Quantitative Reverse Transcriptase PCR; Regulation; Reporter; Rhabdomyosarcoma; Role; Signal Transduction; Skeletal Muscle; Soft tissue sarcoma; Testing; Therapeutic; Transcription Repressor; Transgenic Mice; Tretinoin; Work; aggressive therapy; base; chromatin immunoprecipitation; design; experimental study; gain of function; high risk; in vitro Assay; in vivo; insight; loss of function; medulloblastoma; mouse model; mutant; neoplastic cell; novel; novel therapeutics; overexpression; progenitor; promoter; tumor

Project Summary/Abstract Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in childhood. Despite rigorous clinical trials the survival for children with high-risk RMS has not changed for three decades. The children that do survive often suffer from life-long disfigurements as a result of the aggressive treatment. RMS is subdivided into two major classes, fusion-positive (FP-RMS) and fusion-negative (FN-RMS), based on the presence or absence of the PAX3-FOXO1 or PAX7-FOXO1 gene fusions. RMS resembles developing skeletal muscle and has been speculated to originate from genetically compromised skeletal muscle progenitors. Despite the expression of skeletal muscle master regulator proteins MYOD1 and MYOGENIN, RMS tumors and cells fail to terminally differentiate, suggesting that RMS is an arrested state of muscle development. The molecular underpinnings of the differentiation arrest in RMS and therapeutics to drive differentiation are unknown. The long-term goal is to elucidate the mechanisms that determine the basis for developmental arrest in RMS and design novel, directed drug therapies for RMS. A study recently identified PTEN promoter hypermethylation with decrease PTEN expression in over 90% of FN-RMS tumors. In a RMS genetically engineered mouse model (GEMM), PTEN loss decreased tumor latency, increased tumor penetrance, and much less differentiated tumors more closely resembling the embryonal RMS in children. PTEN loss did not increase mTOR signaling but was localized in the nucleus and increased PAX7 expression and ectopic DBX1 expression. DBX1 is a neuronal specific transcriptional repressor that is ectopically expressed across both human FN-RMS and FP-RMS. Forced DBX1 expression blocks myogenic differentiation in cultured myoblasts. The central hypothesis is that the PTEN-PAX7- DBX1 axis provides a key node in the developmental arrest in RMS and that DBX1 functions as a transcriptional repressor blocking differentiation in RMS. The objective of this proposal is to leverage our robust RMS mouse models coupled with in vitro assays to define the role of PTEN and DBX1 in RMS. To accomplish this objective, we propose the following Specific Aims: 1) Define the role of PTEN loss in RMS. 2) Determine the mechanism of DBX1 regulation in RMS. 3) Identify role of DBX1 in blocking myogenic differentiation in RMS. The proposed studies leverage a simple, rapid RMS GEMM to dissect genes that contribute to RMS biology in vivo and provide insight into the mechanism maintaining an arrested state of differentiation in RMS. We will use gain- and loss- of-function approaches both in vivo and in vitro to dissect the roles of AKT1, mTORC1, PAX7 and DBX1 in modulation of the PTEN loss phenotype. Differentiation therapy of embryonal tumors has proven an efficacious venue for therapy with 13-cis-retinoic acid for neuroblastoma and all-trans-retinoic acid for acute promyelocytic leukemia. Molecular and developmental dissection of RMS will reveal new vulnerabilities to develop new therapeutics to drive terminal differentiation of RMS. These studies will have broad impact as DBX1 is highly expressed in pediatric brain tumors and PTEN perturbations are involved in many cancers.

项目摘要/摘要 横纹肌肉瘤（RMS）是儿童期最常见的软组织肉瘤。尽管进行了严格的临床试验 高风险RMS的儿童的生存已经发生了三十年。生存的孩子 由于侵略性待遇，通常会遭受终身毁容。 RMS分为两个 主要类别，融合阳性（FP-RMS）和融合 - 阴性（FN-RMS），基于存在或不存在 PAX3-FOXO1或PAX7-FOXO1基因融合。 RMS类似于发展骨骼肌，并且已经 推测源自遗传损害的骨骼肌祖细胞。尽管表达了 骨骼肌主调节蛋白myod1和肌根蛋白，RMS肿瘤和细胞无法终止 区分，表明RMS是肌肉发育的被捕状态。分子的基础 RMS和用于推动分化的治疗学的分化停滞尚不清楚。长期目标是 阐明确定RMS和设计小说中发育停滞基础的机制，定向 RMS的药物疗法。一项研究最近鉴定出PTEN启动子高甲基化，而PTEN降低 超过90％的FN-RMS肿瘤表达。在RMS基因工程鼠标模型（GEMM）中，PTEN损失 肿瘤潜伏期降低，肿瘤渗透率增加，而分化的肿瘤更接近得多 类似于儿童的胚胎RMS。 PTEN损失并未增加MTOR信号传导，而是位于 核和PAX7表达和异位DBX1表达增加。 DBX1是一种神经元特异性 转录阻遏物在人FN-RMS和FP-RMS上均可表达。强制DBX1 表达阻碍了培养的肌细胞中的肌源分化。中心假设是PTEN-PAX7- DBX1轴提供了RMS发育停滞的关键节点，并且DBX1用作转录 阻止RMS中的差异化。该建议的目的是利用我们强大的RMS鼠标 模型与体外测定法相结合，以定义PTEN和DBX1在RMS中的作用。为了实现这一目标， 我们提出以下特定目的：1）定义PTEN损失在RMS中的作用。 2）确定机制 RMS中的DBX1调节。 3）确定DBX1在阻断RMS中肌源分化方面的作用。提议 研究利用一个简单的快速RMS GEMM剖析了在体内有助于RMS生物学并提供的基因 深入了解RMS中有被捕状态的机制。我们将使用增益和损失 - 功能在体内和体外接近，以剖析Akt1，mtorc1，pax7和dbx1在 PTEN损耗表型的调节。胚胎肿瘤的分化疗法已证明是有效的 用13-钙摩酸治疗神经母细胞瘤和全反送毒酸的治疗场所，用于急性前临床细胞 白血病。 RMS的分子和发育解剖会揭示出新的脆弱性 驱动RMS终末分化的治疗剂。这些研究将产生广泛的影响，因为DBX1很高 许多癌症中都在小儿脑肿瘤和PTEN扰动中表达。