M(IL-22)介导不对称分裂促进胶质瘤干细胞侵袭的机制研究

Glioblastoma (GBM) is the most common malignant primary brain tumor in adults. Cancer stem cells (CSCs) have been suggested to contribute to the invasion and aggression of GBM. Tumor-associated macrophages (TAMs) are closely correlated with invasive cancer stem cells（ICSCs）, but the mechanism remains unclear. We have found a subgroup of TAMs with the ability of secreting Interleukin-22 (IL-22) as well as being polarized by IL-22, and name this group of TAMs as M(IL-22). M(IL-22) exhibits a specific expression profile and promotes the stemness and invasiveness of GSCs. Since CSCs may differentiate to ICSCs via asymmetric division, we propose that M(IL-22) contributes to invasiveness of GSCs through asymmetric cell division. In this proposal, we intend to observe the distribution of M (IL-22) and analysis its prognostic significance in human glioblastoma specimens. We also propose to construct the asymmetric division model of glioma stem cells, and explore whether M(IL-22) regulates the formation of ICSCs, thereby clarifying the possible mechanisms underneath asymmetric division. This project aims to provide the essential experimental evidence and theoretical basis for the development of a novel therapeutic strategy for glioma patients through specific targeting the tumor-associated macrophages and invasive cancer stem cells.

恶性胶质瘤（GBM）具有高侵袭性，其中侵袭性胶质瘤干细胞(GSC)是GBM复发的关键。肿瘤相关巨噬细胞（TAM）与肿瘤干细胞的侵袭密切相关，但其机制仍不明确。我们前期发现GBM中存在分泌白细胞介素22（IL-22）且可被IL-22极化成M（IL-22）的TAM亚群； M(IL-22)能够显著促进GBM侵袭。基于GSC能够多向分化和不对称分裂，我们提出“M（IL-22）介导GSC不对称分裂促进高侵袭性亚群的形成”的实验假说。本项目拟在检测GBM标本中M（IL-22）分布及与患者的预后关系的基础上，通过分离培养原代细胞、体内体外侵袭模型和IL-22条件敲除小鼠模型等实验，研究M（IL-22）的生物学特征及其对GSC不对称分裂促侵袭的作用，探讨M（IL-22）对GSC不对称分裂的调控及其机制，为阐明胶质瘤微环境中TAM与GSC侵袭的关系、进一步研究靶向治疗药物提供实验基础和理论依据。

恶性胶质瘤（GBM）具有高侵袭性，其中侵袭性胶质瘤干细胞(GSC)是GBM复发的关键。肿瘤相关巨噬细胞（TAM）与肿瘤干细胞的侵袭密切相关，但其机制仍不明确。我们（张翔博士论文：肿瘤相关巨噬细胞对胶质瘤“干性”和侵袭性的调控及机制研究）发现GBM中存在分泌白细胞介素22（IL-22）且可被IL-22极化成M（IL-22）的TAM亚群，而且M(IL-22)能够显著促进GBM侵袭。基因集富集分析发现M(IL-22)的基因表达谱在NABA-matrisome asscoated 基因集和NABA-matrisome secreted factors基因集中具有高富集度；基因芯片比对分析胶质瘤相关M(IL-22)中高表达的分泌型因子显示8个相关基因：CCL8, CXCL2, CXCL9, IL1B, IL1RN, INHBA, TNFSF9和TNFSF8。其中CCL8经ERK1/2信号通路介导促胶质瘤细胞的侵袭和干性形成（Laboratory Investigation. 100:619-629）；CXCL9可以增加蛋白多糖NG2在GBM细胞上的不对称分布，并以剂量递增的方式增加NG2为标志的GBM细胞不对称分裂（图1）；而GSC的异质性和不对称分裂所形成的特殊亚群在单细胞测序和免疫共聚焦显微镜观察实验中得到了证实。我们的实验结果和发现为阐明胶质瘤微环境中TAM与GSC侵袭的关系、进一步研究靶向治疗药物提供实验基础和理论依据。