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，包括弥漫性固有桥脑胶质瘤(DIPG)，代表 是儿童和青少年胶质瘤相关死亡的主要原因。手术切除中的挑战， 对常规化疗的耐药性是导致预后惨淡的原因之一。因此，迫切需要 阐明DIPG的分子基础，并确定治疗这种致命疾病的新药物靶点。体细胞 编码组蛋白H3的15个基因中的一个发生突变，最常见的是H3F3A或HIST1H3B基因 在80%的DIPG肿瘤中发现，用蛋氨酸(H3K27M)取代组蛋白H3赖氨酸27。H3F3A和HIST1H3 编码组蛋白H3变异体H3.3和典型H3.1。在这些“H3K27M肿瘤”中，约80%和 20%为H3.3K27M和H3.1K27M。此外，H3.1K27M和H3.3K27M显示DIPG肿瘤 不同的基因表达特征，并与不同的司机基因突变有关。最近，它已经 已有研究表明，DIPG细胞与周围神经元相互作用，促进细胞增殖和侵袭 DIPG细胞。然而，H3.1K27M DIPG独特的基因表达模式在很大程度上是未知的 调节以促进肿瘤的形成以及肿瘤细胞和神经元之间的相互作用。我们假设 染色质调节剂控制H3.1K27M独特的基因表达模式和肿瘤-神经元相互作用 DIPG肿瘤。为了验证这一假设，我们进行了CRISPR/Cas9筛选，以确定染色质调节因子 当耗尽时，专门降低H3.1K27M细胞的适合度，但不会降低H3.3K27M DIPG细胞的适合度。通过这一努力， 我们发现了CHD2，它是CHD家族染色质重构体的成员。CHD2因其在基因中的作用而为人所知 H3.3的调节和核小体组装，其调节失调与癌症和神经系统有关 综合症。然而，它在H3.1K27M DIPG中的作用是意想不到的。我们发现CHD2的消耗减少了 H3.1K27M和H3.3K27M DIPG轴突导向和神经发生相关基因的表达 细胞。此外，H3.1K27M细胞中CHD2的耗竭导致H3K27me3增加和H3K27减少 乙酰化(H3K27ac)。基于这些令人兴奋的结果，我们建议阐明分子机制。 H3，1K27M DIPG细胞对CHD2的独特依赖性，并检验CHD2的假设 调节这些细胞中与神经元相互作用的基因的表达。此外，我们还将测试 CHD2抑制及其调控事件(H3K27ac、H3K27me3和涉及轴突的基因)的假说 指导)使用患者来源的异种移植(PDX)小鼠模型来折衷肿瘤生长。团结在一起， 拟议的研究将在调控独特基因表达方面提供两个概念性进展 H3.1K27M DIPG信号与肿瘤-神经元相互作用的调节--一个新兴的癌症领域 神经科学。此外，拟议的研究还将提供活体数据，以支持小说的未来发展 针对这种无法治愈的恶性肿瘤的靶向治疗。