SON-mediated RNA splicing in glioblastoma

胶质母细胞瘤中SON介导的RNA剪接

• 批准号: 10428558
• 负责人: Erin Eun-Young Ahn
• 金额: $ 35.03万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-07-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10428558
• 关键词: Affect; Alternative Splicing; Automobile Driving; Biological; Biology; Brain; Cell Cycle Progression; Cells; Complex; DNA Binding; DNA Repair; Data; Data Analyses; Development; Diagnosis; Differentiation and Growth; Epidermal Growth Factor Receptor; Excision; Exons; Future; Gene Abnormality; Gene Expression; Genes; Glioblastoma; Glioma; Hematologic Neoplasms; Heterogeneous-Nuclear Ribonucleoproteins; Impairment; In Vitro; Introns; Knowledge; Malignant Neoplasms; Mediating; Messenger RNA; Molecular; Mutation; Nerve Block; Nuclear; Oncogenic; PDGFRA gene; Patients; Polypyrimidine Tract-Binding Protein; Positioning Attribute; Process; Production; Proteins; RNA; RNA Binding; RNA Splicing; Radiation therapy; Recurrence; Regulation; Research; Role; Sampling; Site; Solid Neoplasm; Specific qualifier value; Splice-Site Mutation; Spliceosomes; TP53 gene; Testing; Therapeutic; Transcript; Up-Regulation; Xenograft Model; base; cell growth; chemotherapy; clinically significant; genome-wide; genome-wide analysis; in vivo; inhibitor; knock-down; nerve stem cell; new therapeutic target; non-genetic; novel strategies; novel therapeutic intervention; patient derived xenograft model; programs; recruit; relating to nervous system; stem cell genes; stem cells; targeted treatment; temozolomide; tumor

PROJECT SUMMARY Glioblastoma multiforme (GBM) is the most common and lethal brain malignancy with a median survival of only one year after diagnosis. Our current knowledge of the underlying basis of GBM centers mostly on several recurrent mutations in specific genes. However, non-genetic factors contributing to GBM development and progression are largely unknown. Due to our poor understanding of GBM biology, treatment options are limited to chemotherapy (temozolomide, TMZ) combined with radiotherapy. Thus, new therapeutic approaches are desperately needed to treat this deadly tumor. Emerging evidence has demonstrated that aberrant RNA splicing due to splice site mutations and/or splicing factor mutations drives oncogenic gene expression in multiple types of solid tumors and hematologic malignancies. In GBM, a few RNA splicing factors, including polypyrimidine tract-binding protein 1 (PTBP1) and hnRNP A2B1 have been recently identified as driving factors in oncogenic splicing, indicating that RNA splicing is a critical, yet to be explored, mechanism that governs a broad range of oncogenic gene expression. Our extensive preliminary data demonstrated that SON, a large nuclear speckle protein possessing DNA- and RNA-binding abilities, is highly upregulated in GBM patient samples, and there is a strong correlation between SON upregulation and short patient survival. We found that SON facilitates expression of PTBP1, thereby activating the PTBP1-meditated oncogenic splicing program. In contrast, SON inhibits the expression of PTBP2, a splicing factor required for neural exon inclusion and neural differentiation. We further revealed that SON regulates the intron removal process at the constitutive splice site in the PTBP1 transcript and regulates cassette exon inclusion/skipping at the alternative splice site in the PTBP2 transcript. We also demonstrated that SON knockdown markedly inhibits GBM cell growth and neural stem cell gene expression, and SON depletion renders patient-derived glioma stem cells (GSCs) sensitive to TMZ in vitro. Based on our preliminary data, we hypothesize that SON is a master RNA splicing regulator positioned at the apex of the splicing factor hierarchy that affects both constitutive and alternative RNA splicing, consequently turning on the oncogenic splicing program and blocking neural splicing. Thus, SON could represent a promising novel therapeutic target for GBM. To test this hypothesis, we propose to dissect the molecular mechanisms of SON functions in the regulation of constitutive and alternative RNA splicing in GBM (Aim 1), and to determine the therapeutic potential of targeting SON in vivo (Aim 2). Successful completion of this proposed study will significantly advance our knowledge of abnormal gene expression in GBM and provide a fundamental rationale for future endeavors to develop SON inhibitors.

项目摘要 多形性胶质母细胞瘤（GBM）是最常见和致命的脑恶性肿瘤， 诊断后一年。我们目前对GBM基础的了解主要集中在几个方面 特定基因的反复突变。然而，非遗传因素有助于GBM的发展， 进展在很大程度上未知。由于我们对GBM生物学的了解不足，治疗选择有限 化疗（替莫唑胺，TMZ）联合放疗。因此，新的治疗方法是 迫切需要治疗这种致命的肿瘤新出现的证据表明， 由于剪接位点突变和/或剪接因子突变导致的剪接驱动致癌基因表达， 多种类型的实体瘤和血液恶性肿瘤。在GBM中，一些RNA剪接因子，包括 多聚嘧啶片段结合蛋白1（PTBP 1）和hnRNP A2 B1最近被鉴定为驱动 致癌剪接中的因子，表明RNA剪接是一个关键的，但尚待探索的机制， 控制着广泛的致癌基因表达。我们广泛的初步数据表明，SON， 一种具有DNA和RNA结合能力的大核斑点蛋白，在GBM中高度上调 患者样本，并且SON上调和短患者存活之间存在强相关性。我们 发现SON促进PTBP 1的表达，从而激活PTBP 1介导的致癌剪接 程序.相反，SON抑制PTBP 2的表达，PTBP 2是神经外显子包含所需的剪接因子 和神经分化。我们进一步揭示了SON调节内含子的去除过程， PTBP 1转录物中的组成性剪接位点，并调节在选择性剪接位点的盒外显子包含/跳跃。 PTBP 2转录物中的剪接位点。我们还证明了SON敲低显著抑制GBM细胞 生长和神经干细胞基因表达，以及SON耗竭使患者来源的胶质瘤干细胞 （GSCs）对TMZ敏感。基于我们的初步数据，我们假设SON是一个主RNA， 剪接调节子位于剪接因子层级的顶点，其影响组成性和 选择性RNA剪接，从而开启致癌剪接程序并阻断神经剪接。 因此，SON可能是GBM的一个有前途的新治疗靶点。为了验证这一假设，我们建议 分析SON在组成性和替代性RNA调节中的分子机制， GBM中的剪接（目的1），并确定体内靶向SON的治疗潜力（目的2）。 这项研究的成功完成将大大提高我们对异常基因的认识。 GBM中的表达，并为未来努力开发SON抑制剂提供基本原理。