POU3F2通过Notch1-Survivin轴对脑胶质瘤恶性生物学行为的调控及其分子机制研究

Gliomas are among the cancers with the worst prognosis, mainly due to their infiltrative growth. In our previous study, the expression of POU3F2, a member of embryonic stem cell associated transcription factor, increasing with tumor grade in gliomas, suggesting a possible role in tumor progression. Meanwhile, high expression of POU3F2 was related to worse prognosis in glioma patients. Bioinformatic analysis implied that POU3F2 was enriched in pathways of cell cycle regulation and might contributed to glioma progression via Notch1-Survivin signaling axis. In this project, the clinical significance and potential function of POU3F2 in malignant gliomas were investigated. Firstly, clinical data was obtained from The Cancer Genome Atlas (TCGA). In particular, GO and KEGG analysis were performed to predict the potential functions of POU3F2. Afterwards, Cell Counting Kit-8, Western blotting, flow cytometry and limiting dilution assays were used to investigate the effect of POU3F2 on cell proliferation, cell cycle progression, apoptosis, as well as the renewal ability of glioma stem cells in vitro. Intracranial xenograft model was established to detect the function of POU3F2 in tumor formation in vivo. Importantly, Chromatin Immunoprecipitation (ChIP) and luciferase reporter gene assays were used to elucidate the underlying mechanism of POU3F2 in regulating Notch1-Survivin signaling. This project is expected to lay the foundation for revealing the mechanism of glioma progression, as well as provide new ideas for the targeted therapy of malignant glioma.

恶性胶质瘤呈侵袭浸润性生长，手术全切困难，患者预后差。课题组前期研究表明，胚胎干细胞转录因子POU3F2在高级别胶质瘤中表达显著；POU3F2 高表达与胶质瘤患者不良预后相关；POU3F2可能通过Notch1信号通路激活凋亡抑制蛋白Survivin 维持胶质瘤干细胞特性而调节胶质瘤的恶性生物学行为，目前国内外对此尚无报道。本课题拟由POU3F2切入，以胶质瘤的恶性生物学行为为研究对象，通过生物信息学（临床标本及数据库分析），体外实验（胶质瘤干细胞分选、基因沉默及过表达、染色质免疫共沉淀、荧光素酶报告基因检测等），体内实验（荷瘤动物标本检测、生存期分析等）相结合的方法，阐明POU3F2通过Notch1-Survivin轴调控胶质瘤恶性生物学行为的分子机制，揭示POU3F2在胶质瘤中的临床价值，为胶质瘤靶向治疗提供新的思路。

脑胶质瘤是最常见的颅内原发肿瘤，其浸润性生长的特点导致手术全切困难，预后差。胶质瘤的分化状态显著影响肿瘤细胞的恶性程度，干细胞样肿瘤细胞能明显促进胶质瘤的增殖以及治疗抵抗。胶质母细胞瘤中神经系统特异性转录因子POU3F2与其他转录因子共同作用，使胶质母细胞瘤细胞转化为具有干细胞样功能的肿瘤细胞从而促进肿瘤细胞的增殖。本课题组前期结果表明恶性胶质瘤中POU3F2的表达明显升高，且POU3F2可能通过Notch1信号通路调控Survivin的激活而维持胶质瘤干细胞特性促进胶质瘤的恶性生物学行为。.根据项目设计，课题组从临床资料和实验室工作两个方向，共同研究POU3F2在胶质瘤中的作用机制。POU3F2在胶质瘤中的表达水平随胶质瘤级别的增高表达增加，且与患者的生存期负相关。POU3F2（+）的胶质瘤细胞增殖指数高于POU3F2（-）细胞。胶质瘤细胞中POU3F2的过表达会增加克隆和细胞增殖。通过TCGA数据库进行生物信息学分析，POU3F2与Notch1和Survivin具有密切相关性；敲除胶质瘤细胞中的POU3F2后，Notch1和Survivin的表达水平显著下降。将POU3F2过表达、siRNA对照和沉默的胶质瘤细胞进行裸小鼠颅内原位种植，MRI动态观察颅内成瘤情况和生存期，发现POU3F2过表达组全部成瘤，而siRNA对照和沉默组的裸小鼠颅内未成瘤，说明POU3F2作为胶质瘤治疗靶点的潜在价值。.本课题以胶质瘤中POU3F2作为研究对象，通过临床资料及标本分析、生物信息学数据库分析、体外实验和体内实验相结合的方法，探索POU3F2通过Notch1信号通路激活凋亡抑制蛋白Survivin维持胶质瘤干细胞特性而调节胶质瘤恶性生物学行为的机制。这一机制的阐明可为胶质瘤的靶向治疗提供新的思路。