Single-cell RNA-seq Reveals a Developmental Hierarchy and Oncogenic Networks for Initiation of Medulloblastoma [ChIP-Seq]

By utilizing single-cell analysis at different stages of tumorigenesis, we demonstrated a developmental hierarchy of dynamic progenitor pools in murine sonic hedgehog-(SHH) MBs. We identified Olig2+ progenitors as transit-amplifying cells during initial tumorigenic phases. These cells are quiescent stem-like progenitors in full-blown tumors but enriched in therapy-resistant as well as recurrent medulloblastomas. Olig2 ablation or depletion of mitotic Olig2+ progenitors abrogated tumorigenesis. Transcriptome profiling and chromatin occupancy assays revealed that Olig2 activates oncogenic networks including HIPPO- Yap/Taz signaling and Aurora-A/MycN pathways. Co-targeting these oncogenic pathways induced sustained tumor growth arrest. Together, our single-cell analyses uncover unexpected glia-lineage-related Olig2+ progenitor pools critical for medulloblastoma initiation and suggest targeting Olig2-regulated oncogenic pathways as an avenue for therapy. Overall design: 4 ChIP-seq samples and 2 input samples from normal cerebellum and medulloblastoma tissues

本研究通过对不同肿瘤发生阶段的单细胞分析，在小鼠音猬因子（SHH）型髓母细胞瘤（MB）中揭示了动态祖细胞库的发育层级。我们鉴定出Olig2+祖细胞在肿瘤发生初始阶段为过渡扩增细胞；在完全形成的进展期肿瘤中，这类细胞为静息态干细胞样祖细胞，且在治疗抵抗性及复发性髓母细胞瘤中富集。敲除Olig2或清除有丝分裂期Olig2+祖细胞可阻断肿瘤发生。转录组分析与染色质占据实验显示，Olig2可激活包括Hippo-Yap/Taz信号通路及极光激酶A（Aurora-A）/MYCN通路在内的致癌调控网络。联合靶向上述致癌通路可诱导持久的肿瘤生长阻滞。综上，本研究的单细胞分析揭示了此前未被发现的、与胶质细胞谱系相关的Olig2+祖细胞库，其对髓母细胞瘤的发生起始至关重要；同时提示靶向Olig2调控的致癌通路可作为潜在治疗策略。实验设计：从正常小脑组织及髓母细胞瘤组织中获取4个染色质免疫共沉淀测序（ChIP-seq）样本与2个输入对照样本。