Mediators Of Arrested Differentiation In Pediatric Rhabdomyosarcoma

小儿横纹肌肉瘤分化停滞的介质

基本信息

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
项目类别：
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

项目摘要

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.

项目概要/摘要横纹肌肉瘤（RMS）是儿童期最常见的软组织肉瘤。尽管经过严格的临床试验患有高危 RMS 的儿童的生存率三十年来没有改变。幸存下来的孩子们由于积极的治疗，他们常常遭受终生的毁容。 RMS分为两部分主要类别，融合阳性 (FP-RMS) 和融合阴性 (FN-RMS)，基于是否存在 PAX3-FOXO1 或 PAX7-FOXO1 基因融合体。 RMS 类似于发育中的骨骼肌，并且已被推测源自基因受损的骨骼肌祖细胞。尽管表达的是骨骼肌主调节蛋白 MYOD1 和 MYOGENIN、RMS 肿瘤和细胞最终未能区分，表明 RMS 是肌肉发育的停滞状态。的分子基础 RMS 的分化停滞和驱动分化的治疗方法尚不清楚。长期目标是阐明决定 RMS 发育停滞基础的机制，并设计新颖的、定向的 RMS 的药物治疗。最近的一项研究发现 PTEN 启动子高甲基化会导致 PTEN 降低在超过 90% 的 FN-RMS 肿瘤中表达。在 RMS 基因工程小鼠模型 (GEMM) 中，PTEN 缺失肿瘤潜伏期缩短，肿瘤外显率增加，分化程度较低的肿瘤更加紧密类似于儿童胚胎 RMS。 PTEN 缺失并不会增加 mTOR 信号转导，而是局限于细胞核并增加 PAX7 表达和异位 DBX1 表达。 DBX1是神经元特异性的在人类 FN-RMS 和 FP-RMS 中异位表达的转录抑制因子。强制 DBX1 表达阻断培养的成肌细胞的肌原性分化。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 充当转录因子阻遏蛋白阻断 RMS 的分化。该提案的目标是利用我们强大的 RMS 鼠标模型与体外测定相结合，以确定 PTEN 和 DBX1 在 RMS 中的作用。为了实现这一目标，我们提出以下具体目标：1）定义 PTEN 丢失在 RMS 中的作用。 2）确定机制 RMS 中的 DBX1 调节。 3) 确定 DBX1 在阻断 RMS 肌原性分化中的作用。拟议的研究利用简单、快速的 RMS GEMM 来剖析有助于体内 RMS 生物学的基因，并提供深入了解维持 RMS 分化停滞状态的机制。我们将使用收益和损失功能性方法在体内和体外剖析 AKT1、mTORC1、PAX7 和 DBX1 在 PTEN 丢失表型的调节。胚胎肿瘤的分化治疗已被证明是有效的 13-顺式视黄酸治疗神经母细胞瘤和全反式视黄酸治疗急性早幼粒细胞瘤的场所白血病。 RMS 的分子和发育解剖将揭示新的漏洞，以开发新的驱动 RMS 终末分化的治疗方法。这些研究将产生广泛的影响，因为 DBX1 高度 PTEN 扰动与许多癌症有关。