SOX9作为脑胶质瘤分子网络的重要节点促进胶质瘤干细胞干性维持及放疗抵抗性的机制研究

The maintenance of stemness and radioresistance of glioma stem like cells (GSCs) depend on the regulation of a complex tumorigenic molecular network including EGFR, Notch1 and hypoxia. To date，therapeutic strategies targeting a single pathway often result in poor therapeutic effects, making it urgent and necessary to decipher key molecule points regulating the network as potential targets. The novel stem cell transcriptional factor SOX9 is involved in tumorigenesis of many tissues, and induces and maintains neural stem cells. Based on current research about SOX9, our bioinformatics analysis suggest that SOX9 may be a critical point for the above molecule network. Our primary studies demonstrated that the expression levels of SOX9 in glioblastoma are positively correlated with that of EGFR, Notch1 and hypoxia，and high SOX9 expression predicts poor prognosis. SOX9 is specifically more highly expressed in GSCs, and positively regulates stem cell markers SOX2 and Nestin. In addition, SOX9 mRNA was up-regulated in glioblastoma cell lines after irradiation treatment. Based on these findings, the current project will focus to explore the underlying mechanisms of SOX9, acting as a key point for the above molecule network, induced maintenance and radio-resistance of GSCs, by using primary GSC culturing model and taking advantage of gene regulation technologies. The project will provide foundations for establishing new therapeutic strategies against glioblastoma and developing novel approaches targeting SOX9.

胶质瘤干细胞（GSC）的干性维持和放疗抵抗性受EGFR、Notch等多个信号通路组成的复杂分子网络调控。目前针对单个信号通路的研究难以取得理想治疗效果，使得我们不得不进一步探索调控此分子网络的关键分子靶点。新干性转录因子SOX9参与多种肿瘤发生，并可促进神经干细胞干性维持。结合国内外研究，我们采用生物信息学分析指出，SOX9可能是上述分子网络的关键节点。我们研究发现，胶质瘤中SOX9表达水平与EGFR、Notch1等分子正相关，且SOX9表达高者预后差；SOX9特异性高表达于GSC，并正向调节SOX2、Nestin等干细胞因子；放疗处理胶质瘤细胞后SOX9表达上调。基于这些发现，本项目将采用原代培养GSC模型，结合基因调控技术，深入阐明SOX9作为上述分子网络的重要节点，参与调节GSC干性维持和放疗抵抗性的机制，为开辟胶质瘤治疗新策略，寻找基于SOX9的新干预措施奠定基础。

SOX9作为脑胶质瘤分子网络的重要节点参与了胶质瘤干细胞干性维持及胶质瘤的化疗抵抗性。本课题通过构建胶质瘤化疗损伤模型，结合运用生物信息学、蛋白质生物化学、细胞生物学等方法与技术，对SOX9参与调控胶质瘤干细胞干性维持及化疗抵抗性的机制进行了研究。首先我们证明miR-101是胶质瘤发生和发展的重要调节因子。通过双荧光素报告实验证明SOX9是miR-101的直接靶标，miR-101通过靶向SOX9抑制胶质瘤细胞增殖、迁移和侵袭，并抑制胶质瘤的体内生长。研究了SOX9在胶质瘤干细胞干性维持和干细胞自我更新中的功能。利用基因表达谱芯片分析了胶质瘤细胞中SOX9沉默后的差异基因筛选出SOX9调节胶质瘤干细胞干性的下游靶标PDK1，证明SOX9和PDK1通过调节AKT信号通路调控胶质瘤干细胞干性和自我更新。利用TMZ损伤模型研究了SOX9在胶质瘤细胞化疗抵抗性中的功能。研究了SOX9调节胶质瘤细胞化疗抵抗中的作用，证明SOX9-CA9调控AKT通路以及bcl-2/BAX等基因表达是胶质瘤化疗抵抗产生的重要原因，并建立了SOX9调控胶质瘤化疗抵的信号通路。