The fatal diffuse midline gliomas (DMG) are characterized by an undruggable H3K27M mutation in H3.1 or H3.3. K27M impairs normal development by stalling differentiation. The identification of targetable pathways remains very poorly explored. Toward this goal, we undertake a multi-omics approach to evaluate replication timing profiles, transcriptomics, and cell cycle features in DMG cells from both H3.1K27M and H3.3K27M subgroups and perform a comparative, integrative data analysis with healthy brain tissue. DMG cells present differential replication timing in each subgroup, which, in turn, correlates with significant differential gene expression. Differentially expressed genes in S phase are involved in various pathways related to DNA replication. We detect increased expression of DNA replication genes earlier in the cell cycle in DMG cell lines compared to normal brain cells. Furthermore, the distance between origins of replication in DMG cells is smaller than in normal brain cells and their fork speed is slower, a read-out of replication stress. Consistent with these findings, DMG tumors present high replication stress signatures in comparison to normal brain cells. Finally, DMG cells are specifically sensitive to replication stress therapy. This whole genome multi-omics approach provides insights into the cell cycle regulation of DMG via the H3K27M mutations and establishes a pharmacologic vulnerability in DNA replication, which resolves a potentially novel therapeutic strategy for this non-curable disease.

中文翻译：

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多组学方法显示弥漫性中线胶质瘤呈现 DNA 复制改变，并且易受复制应激治疗


致命的弥漫性中线胶质瘤 （DMG） 的特征是 H3.1 或 H3.3 中不可成药的 H3K27M 突变。K27M 通过阻碍分化来损害正常发育。对可靶向途径的鉴定仍然探索得非常少。为了实现这一目标，我们采用多组学方法来评估来自 H3.1K27M 和 H3.3K27M 亚组的 DMG 细胞中的复制时间曲线、转录组学和细胞周期特征，并与健康脑组织进行比较、综合数据分析。DMG 细胞在每个亚组中都存在差异复制时间，这反过来又与显着的差异基因表达相关。S 期差异表达基因参与与 DNA 复制相关的各种途径。与正常脑细胞相比，我们在 DMG 细胞系的细胞周期早期检测到 DNA 复制基因的表达增加。此外，DMG 细胞中复制起点之间的距离比正常脑细胞小，并且它们的分叉速度较慢，这是复制应激的读数。与这些发现一致，与正常脑细胞相比，DMG 肿瘤表现出高复制应激特征。最后，DMG 细胞对复制应激疗法特别敏感。这种全基因组多组学方法提供了通过 H3K27M 突变对 DMG 细胞周期调控的见解，并建立了 DNA 复制中的药理学脆弱性，从而解决了这种不可治愈疾病的潜在新型治疗策略。