Neuroblastoma is a deadly pediatric solid tumor with infrequent recurrent somatic mutations. Particularly, the pathophysiology of tumors without MYCN amplification remains poorly defined. Utilizing an unbiased approach, we performed gene set enrichment analysis of RNA-sequencing data from 498 patients with neuroblastoma and revealed a differentially overexpressed gene signature in MYCN nonamplified neuroblastomas with telomerase reverse transcriptase (TERT) gene overexpression and coordinated activation of oncogenic signaling pathways, including E2Fs, Wnt, Myc, and the DNA repair pathway. Promoter rearrangement of the TERT gene juxtaposes the coding sequence to strong enhancer elements, leading to TERT overexpression and poor prognosis in neuroblastoma, but TERT-associated oncogenic signaling remains unclear. ChIP-seq analysis of the human CLB-GA neuroblastoma cells harboring TERT rearrangement uncovered genome-wide chromatin co-occupancy of Brd4 and H3K27Ac and robust enrichment of H3K36me3 in TERT and multiple TERT-associated genes. Brd4 and cyclin-dependent kinases (CDK) had critical regulatory roles in the expression and chromatin activation of TERT and multiple TERT-associated genes. Epigenetically targeting Brd4 or CDKs with their respective inhibitors suppressed the expression of TERT and multiple TERT-associated genes in neuroblastoma with TERT overexpression or MYCN amplification. ChIP-seq and ChIP-qPCR provided evidence that the CDK inhibitor directly inhibited Brd4 recruitment to activate chromatin globally. Therefore, inhibiting Brd4 and CDK concurrently with AZD5153 and dinaciclib would be most effective in tumor growth suppression, which we demonstrated in neuroblastoma cell lines, primary human cells, and xenografts. In summary, we describe a unique mechanism in neuroblastoma with TERT overexpression and an epigenetically targeted novel therapeutic strategy. SIGNIFICANCE: Epigenetically cotargeting Brd4 and Cdks suppresses human neuroblastoma with TERT overexpression by inhibiting the TERT-associated gene expression networks.

中文翻译：

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具有 TERT 过表达的人类神经母细胞瘤中 TERT 相关基因表达特征的表观遗传靶向。

神经母细胞瘤是一种致命的小儿实体瘤，具有罕见的复发性体细胞突变。特别是，没有 MYCN 扩增的肿瘤的病理生理学仍然不明确。我们采用无偏见的方法对 498 名神经母细胞瘤患者的 RNA 测序数据进行了基因集富集分析，并揭示了端粒酶逆转录酶 (TERT) 基因过度表达和致癌信号通路协调激活的 MYCN 非扩增神经母细胞瘤中差异过度表达的基因特征，包括E2Fs、Wnt、Myc 和 DNA 修复途径。TERT 基因的启动子重排将编码序列与强增强子元件并置，导致神经母细胞瘤中 TERT 过表达和不良预后，但 TERT 相关的致癌信号仍不清楚。对具有 TERT 重排的人类 CLB-GA 神经母细胞瘤细胞的 ChIP-seq 分析揭示了 Brd4 和 H3K27Ac 的全基因组染色质共占以及 TERT 和多个 TERT 相关基因中 H3K36me3 的强烈富集。Brd4 和细胞周期蛋白依赖性激酶 (CDK) 在 TERT 和多个 TERT 相关基因的表达和染色质激活中具有关键的调节作用。表观遗传靶向 Brd4 或 CDKs 及其各自的抑制剂抑制了神经母细胞瘤中 TERT 和多个 TERT 相关基因的表达，并具有 TERT 过表达或 MYCN 扩增。ChIP-seq 和 ChIP-qPCR 提供了 CDK 抑制剂直接抑制 Brd4 募集以激活全局染色质的证据。因此，同时抑制 Brd4 和 CDK 与 AZD5153 和 dinaciclib 对抑制肿瘤生长最有效，我们在神经母细胞瘤细胞系、原代人类细胞和异种移植物中证明了这一点。总之，我们描述了具有 TERT 过表达的神经母细胞瘤的独特机制和表观遗传靶向的新型治疗策略。意义：表观遗传共靶向 Brd4 和 Cdks 通过抑制 TERT 相关基因表达网络来抑制具有 TERT 过表达的人类神经母细胞瘤。