Roles of Chromatin Remodeler CHD2 in Diffuse Midline Glioma with Onco-Histone Mutations

染色质重塑蛋白 CHD2 在具有癌组蛋白突变的弥漫性中线胶质瘤中的作用

• 批准号: 10667276
• 负责人: Zhiguo Zhang
• 金额: $ 41.13万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-03-20 至 2028-02-29
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10667276
• 关键词: ACVR1 gene; ATPase Domain; Acetylation; Adolescent; Amino Acids; CRISPR screen; Catalytic Domain; Cell Communication; Cell Proliferation; Cells; Cessation of life; Child; Chromatin; Complex; DNA Sequence Alteration; Data; Dependence; Development; Diagnosis; Diffuse intrinsic pontine glioma; Disease; EP300 gene; EZH2 gene; Ephrins; Epigenetic Process; Event; Excision; FOSL1 gene; Family; Functional disorder; Future; Gene Expression; Gene Expression Profile; Gene Expression Regulation; Gene Silencing; Genes; Genetic Transcription; Glioma; Heterozygote; Histone H3; Impairment; In Vitro; Invaded; Link; Lysine; Malignant Childhood Neoplasm; Malignant Neoplasms; Methionine; Methylation; Molecular; Mutation; Neurologic; Neurons; Neurosciences; Nucleosomes; Operative Surgical Procedures; Pathogenesis; Pathogenicity; Phenotype; Prognosis; Proliferating; Proteins; Radiation therapy; Receptor Protein-Tyrosine Kinases; Regulation; Regulator Genes; Regulatory Element; Resistance; Role; Signal Transduction; Somatic Mutation; Subgroup; Syndrome; Testing; Variant; axon guidance; chemotherapy; diffuse midline glioma; driver mutation; effective therapy; fitness; histone modification; in vivo; member; migration; mouse model; mutant; neoplastic cell; nervous system disorder; neurogenesis; neuronal tumor; new therapeutic target; novel; oncohistone; p300/CBP-Associated Factor; patient derived xenograft model; protein H(3); recruit; therapeutic target; transcription factor; treatment response; tumor; tumor growth; tumor progression; tumorigenesis

Diffuse midline gliomas (DMG)-H3K27 altered, which include diffuse intrinsic pontine gliomas (DIPG), represent the leading cause of glioma-related deaths in children and adolescents. Challenges in surgical resection, resistance to conventional chemotherapies contribute to the dismal prognosis. Therefore, it is imperative to elucidate the molecular basis of DIPG and to identify novel drug targets for this deadly disease. Somatic mutations at one of the 15 genes encoding histone H3, most frequently at either H3F3A or HIST1H3B gene, are found in 80% of DIPG tumors, replacing histone H3 lysine 27 with methionine (H3K27M). H3F3A and HIST1H3 encode histone H3 variant H3.3 and canonical H3.1, respectively. Of these “H3K27M tumors”, about 80% and 20% are H3.3K27M and H3.1K27M, respectively. Furthermore, H3.1K27M and H3.3K27M DIPG tumors show distinct gene expression signatures and are associated with distinct driver genetic mutations. Recently, it has been shown that DIPG cells interact with surrounding neurons, which promote the proliferation and invasion of DIPG cells. However, it is largely unknown how the unique gene expression pattern of H3.1K27M DIPG is regulated to promote tumorigenesis and the interactions between tumor cells and neurons. We hypothesize that chromatin regulators control the unique gene expression pattern and tumor-neuron interactions in H3.1K27M DIPG tumors. To test this hypothesis, we performed a CRISPR/Cas9 screen to identify chromatin regulators that when depleted specifically reduce the fitness of H3.1K27M, but not H3.3K27M DIPG cells. Through this effort, we discovered CHD2, a member of the CHD family chromatin remodelers. CHD2 is known for its role in gene regulation and nucleosome assembly of H3.3, and its dysregulation is linked to cancer and neurological syndromes. However, its roles in H3.1K27M DIPG were unexpected. We found that CHD2 depletion reduces the expression of genes involved in axon guidance and neurogenesis in H3.1K27M, but not H3.3K27M DIPG cells. Furthermore, CHD2 depletion in H3.1K27M cells resulted in increased H3K27me3 and reduced H3K27 acetylation (H3K27ac). Based on these exciting results, we propose to elucidate molecular mechanisms underlying the unique dependence of H3,1K27M DIPG cells on CHD2, and test the hypotheses that CHD2 regulates the expression of genes in these cells for their interaction with neurons. Furthermore, we will test the hypothesis that inhibition of CHD2 and its regulated events (H3K27ac, H3K27me3 and genes involved in axon guidance) compromises tumor growth using patient derived xenograft (PDX) mouse models. Together, the proposed studies will provide both conceptual advances in the regulation of the unique gene expression signatures in H3.1K27M DIPG and the regulation of the tumor-neuron interactions, an emerging field of cancer neuroscience. Further, the proposed studies will also provide in vivo data to support future development of novel targeted therapies for this incurable malignancy.

弥漫性中线胶质瘤 (DMG)-H3K27 改变，包括弥漫性内在桥脑胶质瘤 (DIPG)，代表 儿童和青少年神经胶质瘤相关死亡的主要原因，手术切除面临的挑战。 对传统化疗的耐药性导致预后不良。 阐明 DIPG 的分子基础并确定这种致命疾病的新药物靶点。 编码组蛋白 H3 的 15 个基因之一的突变，最常见的是 H3F3A 或 HIST1H3B 基因， 存在于 80% 的 DIPG 肿瘤中，用蛋氨酸 (H3K27M) 取代组蛋白 H3 赖氨酸 27。 在这些“H3K27M 肿瘤”中，约 80% 和 80% 分别编码组蛋白 H3 变体 H3.3 和典型 H3.1。 20%分别为H3.3K27M和H3.1K27M。此外，H3.1K27M和H3.3K27M DIPG肿瘤显示 最近，它与不同的驱动基因突变相关。 研究表明，DIPG 细胞与周围神经元相互作用，促进细胞增殖和侵袭。 然而，H3.1K27M DIPG 的独特基因表达模式究竟如何，目前还不清楚。 调节促进肿瘤发生以及肿瘤细胞和神经元之间的相互作用。 染色质调节因子控制 H3.1K27M 中独特的基因表达模式和肿瘤-神经元相互作用 为了检验这一假设，我们进行了 CRISPR/Cas9 筛选，以确定染色质调节因子 当耗尽时，会专门降低 H3.1K27M 的适应性，但不会降低 H3.3K27M DIPG 细胞的适应性。 我们发现了 CHD2，它是 CHD 染色质重塑家族的成员，因其在基因中的作用而闻名。 H3.3 的调节和核小体组装，其失调与癌症和神经系统疾病有关 然而，它在 H3.1K27M DIPG 中的作用是出乎意料的，我们发现 CHD2 耗竭会减少。 H3.1K27M 中参与轴突引导和神经发生的基因表达，但 H3.3K27M DIPG 中不表达 此外，H3.1K27M 细胞中的 CHD2 缺失导致 H3K27me3 增加和 H3K27 减少 基于这些令人兴奋的结果，我们建议阐明分子机制。 揭示了 H3,1K27M DIPG 细胞对 CHD2 的独特依赖性，并检验了 CHD2 的假设 调节这些细胞中基因的表达以与神经元相互作用。 假设抑制 CHD2 及其调节事件（H3K27ac、H3K27me3 和参与轴突的基因） 指南）使用患者来源的异种移植（PDX）小鼠模型来损害肿瘤生长。 拟议的研究将提供独特基因表达调节的概念进展 H3.1K27M DIPG 中的特征和肿瘤-神经元相互作用的调节，这是一个新兴的癌症领域 此外，拟议的研究还将提供体内数据以支持新颖的未来发展。 针对这种无法治愈的恶性肿瘤的靶向治疗。