内皮细胞促进CD133阴性胶质瘤细胞干样表型的机制研究

Cancer stem-like cell is the main source of tumor initiation, propagation, resistance to treatment and recurrence. The endothelial cell maintains the stemness of glioma cell by increasing of self-renewal ability in CD133-positive glioma stem-like cell. In recently research，we found that endothelial cell could promote stem-like cell phenotypes of CD133-negative glioma cell, accompanying with up-regulation of SDF/CXCR4 gene expression and activation of Hedgehog-Gli1 pathway. Combined with literatures,we presume that endothelial cell can promote stem-like cell phenotypes of CD133-negative glioma cell through SDF/CXCR4-HH-Nanog pathway.It may be an alternative mechanism of endothelial cell maintaining the stemness of glioma cell. In this study,the CD133-negative glioma cell will be sorted by immuno-magnetic beads combined with flow cytometry in vitro. The effects on biological characteristcs (especially stem-like cell features) of CD133-negative glioma cell induced by endothelial cell will be observed on culture cells and xenograft experiment in mice through immunofluorescence, confocal laser scanning microscope, RT-PCR, RNA interference techniques. The roles and relationships between CXCR4 and HH-nanog in the process will also be investigated.The results will increase the theoretical knowledge about enrichment of glioma stem-like cells in perivascular microenvironment,and enhance the understanding of molecular mechanism of maintaining stem-like cell features in glioma. It is significant to look for a more effective therapetical strategy for glioma.

肿瘤干样细胞是肿瘤发生、演进、治疗抵抗和复发的主要根源。既往认为胶质瘤中内皮细胞可通过促进CD133阳性的胶质瘤干细胞自我更新来维持其干性。最近我们发现内皮细胞可促进CD133阴性的胶质瘤细胞干样表型，并有SDF/CXCR4表达明显增多。结合文献，我们提出"内皮细胞通过SDF/CXCR4-HH-Nanog通路促进CD133阴性胶质瘤细胞干样表型可能是内皮细胞维持胶质瘤细胞干性的又一重要机制"的假说。本研究通过体外细胞共培养和体内移植瘤模型实验，采用磁珠分选、免疫荧光、激光共聚焦显微术、RT-PCR及基因功能干扰等技术方法，观测内皮细胞对CD133阴性胶质瘤细胞生物学特性(特别是干样细胞特性)的影响，并探讨CXCR4与HH-Nanog在其中的作用及关系。项目结果可丰富血管旁胶质瘤干样细胞富集的理论知识，为深入了解胶质瘤干样细胞维持的分子机制以及寻找更有效的胶质瘤治疗方案奠定基础，有重要意义。

内皮细胞（EC）是肿瘤干细胞龛的重要组成部分，在肿瘤干细胞的“干性”中具有重要作用，认为胶质瘤血管旁GSC富集主要是由于内皮细胞促进 GSC 的自我更新所致。我们观察到与内皮细胞共培养能显著促进CD133阴性胶质瘤细胞向CD133阳性 胶质瘤细胞转化，促进CD133阴性胶质瘤细胞干性相关基因的表达和体外成球能力及体内成瘤能力，并发现内皮细胞通过SDF/CXCR4-HH-Nanog轴促进CD133阴性胶质瘤细胞干样表型。