Background/Objectives: CSCs are critical drivers of the tumor and stem cell phenotypes of glioblastoma (GBM) cells. Chromatin modifications play a fundamental role in driving a GBM CSC phenotype. The goal of this study is to further our understanding of how stem cell-driving events control changes in chromatin architecture that contribute to the tumor-propagating phenotype of GBM.Methods: We utilized computational analyses to identify a subset of clinically relevant genes that were predicted to be repressed in a Polycomb repressive complex 2 (PRC2)-dependent manner in GBM upon induction of stem cell-driving events. These associations were validated in patient-derived GBM neurosphere models using state-of-the-art molecular techniques to express, silence, and measure microRNA (miRNA) and gene expression changes. Advanced Poly(β-amino ester) nanoparticle formulations (PBAEs) were used to deliver miRNAs in vivo to orthotopic human GBM tumor models.Results: We show that glioma stem cell (GSC) formation and tumor propagation involve the crosstalk between multiple epigenetic mechanisms, resulting in the repression of the miRNAs that regulate PRC2 function and histone H3 lysine 27 tri-methylation (H3K27me3). We also identified miR-217-5p as an EZH2 regulator repressed in GSCs and showed that miR-217-5p reconstitution using advanced nanoparticle formulations re-activates the PRC2-repressed genes, inhibits GSC formation, impairs tumor growth, and enhances the effects of ionizing radiation in an orthotopic model of GBM.Conclusions: These findings suggest that inhibiting PRC2 function by targeting EZH2 with miR-217-5p advanced nanoparticle formulations could have a therapeutic benefit in GBM.
背景/目的：胶质母细胞瘤（GBM）细胞的肿瘤与干细胞表型主要由肿瘤干细胞（CSCs）驱动。染色质修饰在塑造GBM肿瘤干细胞表型中起着基础性作用。本研究旨在深入探讨干细胞驱动事件如何调控染色质结构变化，从而促进GBM的肿瘤增殖表型。 方法：我们通过计算分析鉴定出一组临床相关基因，这些基因在干细胞驱动事件诱导下，预计会以多梳抑制复合物2（PRC2）依赖的方式在GBM中被抑制。利用先进的分子技术，在患者来源的GBM神经球模型中验证了这些关联，包括表达、沉默以及测量微小RNA（miRNA）和基因表达变化。采用先进的聚（β-氨基酯）纳米颗粒制剂（PBAEs）在体内向原位人GBM肿瘤模型递送miRNA。 结果：我们发现，胶质瘤干细胞（GSC）的形成和肿瘤增殖涉及多种表观遗传机制之间的相互作用，导致调控PRC2功能和组蛋白H3赖氨酸27三甲基化（H3K27me3）的miRNA受到抑制。我们鉴定出miR-217-5p作为EZH2的调控因子在GSC中被抑制，并证明使用先进纳米颗粒制剂重建miR-217-5p可重新激活PRC2抑制的基因，抑制GSC形成，削弱肿瘤生长，并在GBM原位模型中增强电离辐射的疗效。 结论：这些发现表明，通过miR-217-5p先进纳米颗粒制剂靶向EZH2以抑制PRC2功能，可能对GBM具有治疗益处。
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