Tomita Yusuke, Shimazu Yosuke, Somasundaram Agila, Tanaka Yoshihiro, Takata Nozomu, Ishi Yukitomo, Gadd Samantha, Hashizume Rintaro, Angione Angelo, Pinero Gonzalo, Hambardzumyan Dolores, Brat Daniel J, Hoeman Christine M, Becher Oren J
Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.
Department of Neurosurgery and Neuroendovascular Surgery, Hiroshima City Hiroshima Citizens Hospital, Hiroshima, Japan.
Glia. 2022 Sep;70(9):1681-1698. doi: 10.1002/glia.24189. Epub 2022 May 7.
Diffuse midline glioma (DMG) is a type of lethal brain tumor that develops mainly in children. The majority of DMG harbor the K27M mutation in histone H3. Oligodendrocyte progenitor cells (OPCs) in the brainstem are candidate cells-of-origin for DMG, yet there is no genetically engineered mouse model of DMG initiated in OPCs. Here, we used the RCAS/Tv-a avian retroviral system to generate DMG in Olig2-expressing progenitors and Nestin-expressing progenitors in the neonatal mouse brainstem. PDGF-A or PDGF-B overexpression, along with p53 deletion, resulted in gliomas in both models. Exogenous overexpression of H3.3K27M had a significant effect on tumor latency and tumor cell proliferation when compared with H3.3WT in Nestin+ cells but not in Olig2+ cells. Further, the fraction of H3.3K27M-positive cells was significantly lower in DMGs initiated in Olig2+ cells relative to Nestin+ cells, both in PDGF-A and PDGF-B-driven models, suggesting that the requirement for H3.3K27M is reduced when tumorigenesis is initiated in Olig2+ cells. RNA-sequencing analysis revealed that the differentially expressed genes in H3.3K27M tumors were non-overlapping between Olig2;PDGF-B, Olig2;PDGF-A, and Nestin;PDGF-A models. GSEA analysis of PDGFA tumors confirmed that the transcriptomal effects of H3.3K27M are cell-of-origin dependent with H3.3K27M promoting epithelial-to-mesenchymal transition (EMT) and angiogenesis when Olig2 marks the cell-of-origin and inhibiting EMT and angiogenesis when Nestin marks the cell-of-origin. We did observe some overlap with H3.3K27M promoting negative enrichment of TNFA_Signaling_Via_NFKB in both models. Our study suggests that the tumorigenic effects of H3.3K27M are cell-of-origin dependent, with H3.3K27M being more oncogenic in Nestin+ cells than Olig2+ cells.
弥漫性中线胶质瘤（DMG）是一种主要发生在儿童中的致命性脑肿瘤。大多数DMG在组蛋白H3中存在K27M突变。脑干中的少突胶质前体细胞（OPC）是DMG的候选起源细胞，但目前尚无在OPC中起始的DMG基因工程小鼠模型。在此，我们使用RCAS/Tv-a禽逆转录病毒系统在新生小鼠脑干中表达Olig2的祖细胞和表达巢蛋白的祖细胞中生成DMG。在两个模型中，PDGF-A或PDGF-B的过表达以及p53的缺失均导致了胶质瘤的形成。与巢蛋白阳性细胞中的H3.3野生型（H3.3WT）相比，H3.3K27M的外源性过表达对肿瘤潜伏期和肿瘤细胞增殖有显著影响，但在Olig2阳性细胞中则不然。此外，在PDGF-A和PDGF-B驱动的模型中，相对于巢蛋白阳性细胞，在Olig2阳性细胞中起始的DMG中H3.3K27M阳性细胞的比例显著更低，这表明当在Olig2阳性细胞中起始肿瘤发生时，对H3.3K27M的需求降低。RNA测序分析显示，H3.3K27M肿瘤中差异表达的基因在Olig2;PDGF-B、Olig2;PDGF-A和巢蛋白;PDGF-A模型之间不重叠。对PDGFA肿瘤的基因集富集分析（GSEA）证实，H3.3K27M的转录组效应取决于起源细胞，当Olig标记起源细胞时，H3.3K27M促进上皮-间质转化（EMT）和血管生成，而当巢蛋白标记起源细胞时，H3.3K27M抑制EMT和血管生成。我们确实观察到在两个模型中H3.3K27M促进TNFA_Signaling_Via_NFKB的负富集存在一些重叠。我们的研究表明，H3.3K27M的致瘤作用取决于起源细胞，H3.3K27M在巢蛋白阳性细胞中比在Olig2阳性细胞中更具致癌性。
