成胶质细胞瘤U87干细胞样细胞的培养及其代谢表型与成瘤能力鉴定

Culture of glioblastoma U87 stem-like cells and identification of its metabolic phenotype and tumorigenic ability

目的培养成胶质细胞瘤U87干细胞样细胞(U87 SLCs),检测其干性标志物的水平、线粒体呼吸能力和体内成瘤能力。方法DMEM/F-12中添加B-27以及生长因子EGF和bFGF作为无血清干细胞培养基培养U87 SLCs;悬浮培养U87 SLCs使用神经球培养法,贴壁培养U87 SLCs通过在培养表面包被Matrigel基质胶实现;通过RT-qPCR和Western blot检测培养物的干性标志物mRNA和蛋白质水平;通过流式细胞测量术检测培养物中CD133+细胞的比例;通过Seahorse实时细胞代谢分析检测细胞耗氧速率的变化;通过接种动物皮下移植瘤验证细胞成瘤能力的改变。结果干细胞培养基中的U87 SLCs在1周内即会成长为典型的细胞球形态,细胞球在培养过程中会不断增大;在贴壁剂合适的浓度下,U87 SLCs可以在干细胞培养基中完好地平铺贴壁增殖;CD133、nestin、OLIG2、CD44、CD15、整合素α6(ITGA6)等干性标志物的mRNA表达水平在两种方式培养后与U87相比均显著提升(P<0.05),CD133和nestin的蛋白水平在两种方式培养后也均升高(P<0.05);U87 SLCs展现出了更高的线粒体储备呼吸能力(P<0.05);U87 SLCs能够以更少的接种细胞数形成更大的皮下肿瘤(P<0.05),U87 SLCs体内增殖更加迅速,具有更强的成瘤能力。结论U87 SLCs具有典型的干性特征,是一个良好的干性更高的肿瘤细胞模型。

Objective To cultivate glioblastoma U87 stem-like cells(SLCs)and to detect the level of stemness biomarkers,mitochondrial respiratory capacity and the capacity of in vivo tumorigenesis.Methods B-27,growth factors EGF and bFGF was added into DMEM/F-12 culture in serum-free stem cell culture medium for U87 SLCs.Suspended culture of U87 SLCs was suspended using the neuro-sphere formation assay,while adherent culture of U87 SLCs was achieved by coating Matrigel matrix on the culture surface.The mRNA and protein level of stemness biomarkers in culture were detected using real-time quantitative PCR and Western blot.The proportion of CD133+cells in culture was detected by flow cytometry.The changes of cell oxygen consumption rate were detected by Seahorse cell metabolism analysis.Cell tumorigenesis ability was verified by subcutaneous tumor transplantation in animals.Results U87 SLCs in stem cell culture medium would grow into typical sphere morphology within one week,and the spheres would continue to grow as the culture process prolongs.At the appropriate concentration of adhesive,U87 SLCs adhered to and grow well in stem cell culture medium.The mRNA transcription of stemness biomarkers such as CD133,nestin,OLIG2,CD44,CD15,and integrinα6(ITGA6)was significantly increased as found in both culture methods,and the protein levels of CD133 and nestin were also increased under both methods(P<0.05).U87 SLCs showed higher mitochondrial reserve respiratory capacity(P<0.05).U87 SLCs could form larger subcutaneous tumors with fewer inoculated cells(P<0.05),and grew faster in vivo with stronger tumorigenic ability.Conclusions U87 SLCs have typical stemness characteristics and may function as tumor cell model with higher stemness properties.