Nanog基因在脑肿瘤干细胞中的表达及意义

Expression of Nanog in brain tumor stem cells

目的 探讨Nanog基因在脑肿瘤干细胞（BTSCs）的表达以及生物学意义.方法 无血清悬浮培养法从U87胶质瘤细胞株分离培养BTSCs.免疫细胞化学染色和RT-PCR方法检测U87肿瘤细胞及其BTSCs中Nanog的表达,双重免疫细胞化学染色法检测Nanog/CD133共表达情况.结果 在U87胶质瘤细胞株中成功分离培养出BTSCs,Nanog蛋白在U87肿瘤细胞和BTSCs中的阳性率分别为（64.1±18.2）%和（97.2±1.8）%,且Nanog＋/CD133＋细胞共表达于部分细胞中;Nanog mRNA相对含量在U87肿瘤细胞和BTSCs中分别为0.3851±0.0771和0.6032±0.1223,差异有统计学意义（P＜0.05）.结论 U87细胞株中存在BTSCs.Nanog在U87细胞株中高表达,在BTSCs中表达水平高于U87肿瘤细胞且Nanog与CD133存在共表达,表明Nanog与BTSCs关系密切.

Objective To detect the expression of Nanog in glioma cell line U87 and the relationship with BTSCs.Methods BTSCs were isolated from glioma cell line U87 and cultured in simplified serum-free neural stem cell medium by nanosphere suspension culture method spheres,and purified continuously through the monoclonal formation experiment.The immunofluorescence staining of cells was employed to identify the BTSCs and differentiated cells.The expression of Nanog mRNA was examined by RT- PCR and Nanog protein was detected by immunocytochemistry in U87 and BTSCs respectively.Double immunocytochemistry staining was used to detect the co- expressions of Nanog/CD133.Methods BTSCs were isolated ,cultured and purified successfully from glioma cell line U87.Both Nanog mRNA and protein were expressed in U87 and BTSCs.The expression rate of immunopositive cells was （64.1 ±18.2）% in U87 and （97.2±1.8）% in BTSCs respectively（t =5.719,P =0.000）.The Nanog＋/CD133＋ cells could be found co-expressed in U87 and BTSCs by using double immunocytochemistry s taining.The relative level of Nanog expression was 0.3851 ±0.0771 in U87 and0.6032±0.1223 in BTSCs（t =4.770,P =0.000）.Conclusion BTSCs exist in glioma cell line U87 in vitro.The levels of Nanog expression in BTSCs were higher than that in U87.Nanog expression was associated with the genesis and differentiation state of glioma.The overexpression of Nanog and co- expression of Nanog/CD133 showed that it might contribute to the existence of BTSCs,which lay a foundation to the further explore its role in biological behaviour of glioma.Expression of Nanog in U87 indicated the close relationship between glioma and stem cell,and suggested Nanog may play a critical role in the development of glioma.