Regulation and function of HOX genes in Ewing sarcoma pathogenesis

HOX基因在尤文肉瘤发病机制中的调控和功能

基本信息

批准号：
10056212
负责人：
Elizabeth R Lawlor
金额：
$ 42.97万
依托单位：
SEATTLE CHILDREN'S HOSPITAL
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-12-18 至 2022-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10056212
关键词：
3-Dimensional Adolescence Affect Binding Biological Assay Bromouridine sequencing Cell Death Cell Death Inhibition Cells Child Chromatin Chromatin Structure Complex Connective and Soft Tissue Neoplasm Cytotoxic Chemotherapy Data Data Set Dependence Development Disease Down-Regulation EWS-FLI1 fusion protein Embryo Embryonic Development Enhancers Epigenetic Process Ewings sarcoma FLI1 gene Gene Expression Genes Genetic Genetic Transcription Growth Homeobox Genes In Vitro Limb Development MLL gene Maintenance Malignant Childhood Neoplasm Mediating Menin Mesenchymal Modeling Molecular Conformation Oncogene Deregulation Oncogenes Oncogenic Pathogenesis Pathway interactions Patients Pharmacotherapy Phenotype Play Polycomb Proteins Publishing Regulation Reporting Role Solid Neoplasm Technology Testing Therapeutic Tissues Transcriptional Regulation Tumorigenicity base chromatin immunoprecipitation chromatin remodeling epigenetic drug histone modification in silico in vivo inhibitor/antagonist innovation knock-down leukemia leukemogenesis malignant phenotype mortality next generation sequencing novel novel strategies novel therapeutics organ growth overexpression postnatal development preclinical development programs promoter protein protein interaction recruit small molecule inhibitor spatiotemporal stem stem cells targeted treatment therapeutic evaluation transcription factor tumor tumor growth tumor progression tumorigenesis tumorigenic validation studies young adult

项目摘要

PROJECT SUMMARY Hijacking of normal developmental programs is a common mechanism of tumorigenesis and epigenetic deregulation of developmental transcription programs is central to the genesis of most, if not all, pediatric cancers. Ewing sarcomas, aggressive bone and soft tissue tumors that predominately arise in adolescence, continue to be associated with high rates of mortality and novel approaches to therapy are needed. Ewing sarcomas are characterized by the presence of pathognomonic driver fusion oncogenes, most commonly EWS/FLI1, and their likely cellular origin is mesenchymal stem/progenitor cells (MSC). EWS/FLI1 initiates tumorigenesis by inducing widespread disruption of transcriptional regulation as a consequence of altered recruitment of chromatin remodelers to target gene enhancers and promoters. We have reported that posterior HOXD genes, in particular HOXD13, are aberrantly over-expressed by Ewing sarcoma and that posterior HOXD genes contribute to maintenance of the tumorigenic phenotype. Our preliminary studies suggest that EWS/FLI1 can induce expression of HOXD13, in a cell context dependent fashion, and that this activation is mediated by aberrant activation of developmental enhancers that are otherwise active in only very discrete spatiotemporal developmental windows. In addition, chromatin immunoprecipitation (ChIP) studies have demonstrated that in EWS/FLI1+ cells the HOXD13 promoter is preferentially enriched with the MLL- dependent activating histone modification H3K4me3 and bound by both MLL and menin proteins. Significantly, exposure of Ewing sarcoma cells to novel small molecule inhibitors of MLL:menin interaction, that are currently in preclinical development for MLL-fusion positive leukemias, leads to a dramatic loss tumorigenicity and concomitant loss posterior HOXD gene expression. Thus, these studies demonstrate that that, like MLL-fusion positive leukemias, maintenance of the oncogenic phenotype of Ewing sarcoma is critically dependent on MLL:menin-dependent activation of developmental HOX genes. In this proposal, we will test the hypothesis that HOXD13 functions an obligate cooperative oncogene in Ewing sarcoma and that dependency on its continued expression presents a previously unrecognized tumor-specific vulnerability that can be therapeutically exploited. In Aim 1 will use innovative Bru-seq technologies and functional validation studies to define the downstream transcriptional targets of HOXD13 that promote tumorigenicity. In Aim 2 we will use targeted ChIP assays and chromatin conformation studies to determine how EWS/FLI1 leads to epigenetic activation of HOXD13. In Aim 3 we will test the therapeutic potential of MI-503, a small molecule inhibitor of MLL:menin protein:protein interaction, in in vivo tumor models. These studies will together elucidate the contribution of HOXD13 to Ewing sarcoma pathogenesis and test the potential of a new class of epigenetic modifying agents for Ewing sarcoma-targeted therapies.

项目摘要劫持正常发育计划是肿瘤发生和表观遗传的常见机制发育转录程序的放松管制是大多数（如果不是全部）儿科的起源的核心癌症。尤因肉瘤，侵袭性骨和软组织肿瘤，主要出现在青春期中继续与高死亡率和新颖的治疗方法有关。尤因肉瘤的特征是存在病理驱动融合肿瘤，最常见 EWS/FLI1及其可能的细胞起源是间充质干/祖细胞（MSC）。 EWS/FLI1启动由于改变而导致转录调节的广泛破坏，肿瘤发生因素募集染色质重塑剂靶向基因增强子和启动子。我们报告了后部 HOXD基因，尤其是HOXD13，被EWING肉瘤异常过表达和后部 HOXD基因有助于维持肿瘤性表型。我们的初步研究表明 ews/fli1可以以依赖性的方式诱导hoxd13的表达，并且这种激活是通过异常激活发育增强剂的激活，这些激活仅在非常离散的情况下活跃时空发育窗口。此外，染色质免疫沉淀（CHIP）研究具有证明在EWS/FLI1+细胞中，HOXD13启动子优先富含MLL- 依赖于激活组蛋白修饰H3K4ME3并由MLL和Menin蛋白结合。显著地， Ewing肉瘤细胞暴露于新型的小分子抑制剂MLL：MENIN相互作用，目前是在MLL融合阳性白血病的临床前发育中，导致巨大损失肿瘤性和伴随损失后HOXD基因表达。因此，这些研究表明，像MLL融合一样阳性白血病，ewing肉瘤的致癌表型的维持至关重要 MLL：Menin依赖性发育基因的激活。在此提案中，我们将检验假设 HOXD13在尤因肉瘤中起着强大的合作癌性的作用，并且对其依赖性继续表达表现出先前未识别的肿瘤特异性脆弱性剥削治疗。在AIM 1中，将使用创新的BRU-SEQ技术和功能验证研究来定义促进肿瘤性的HOXD13的下游转录靶标。在AIM 2中，我们将使用靶向芯片分析和染色质构象研究，以确定EWS/FLI1如何导致表观遗传 HOXD13的激活。在AIM 3中，我们将测试MI-503的治疗潜力，Mi-503是一个小分子抑制剂 MLL：Menin蛋白：蛋白质相互作用，体内肿瘤模型。这些研究将共同阐明 HOXD13对EWING肉瘤发病机理的贡献并测试了新的表观遗传学的潜力修饰ewing肉瘤靶向疗法的剂。