mTOR信号通路调控CD133阳性胶质瘤干细胞自我更新的分子机制  

mTOR Signaling Pathway Regulates Self-renewal of CD133 Positive Glioma Stem Cells

作　　者：付军[1,2] 刘晓梅[1,2] 陈忠平[1,2] 

机构地区：[1]华南肿瘤学国家重点实验室,广东广州510060 [2]中山大学肿瘤防治中心神经外科/神经肿瘤科,广东广州510060

出　　处：《中国神经肿瘤杂志》2010年第2期75-81,共7页Chinese Journal of Neuro-Oncology

基　　金：国家自然科学基金(No.30772551)

摘　　要：背景与目的:mTOR(mammalian target of rapamycin)信号通路异常活化和高级别胶质瘤患者的预后不良相关。本研究探讨mTOR信号通路调控胶质瘤干细胞(GSCs)自我更新相关的分子机制。方法:采用CD133免疫磁珠分选CD133阳性胶质瘤干细胞。Western blot检测mTOR信号通路组分p-S6K、p-S6和干细胞自我更新相关基因Bmi-1的表达水平;Rapamycin(RPA)阻断mTOR信号通路后,用肿瘤球形成实验评价干预mTOR信号通路对胶质瘤干细胞自我更新的影响;统计学处理采用SPSS11.0统计分析软件分析。结果:CD133阳性胶质瘤干细胞表达较高水平的mTOR信号通路组分p-S6K、p-S6和干细胞自我更新相关分子Bmi-1。通过rapamycin阻断mTOR信号通路,可诱导胶质瘤干细胞谱系分化,同时显著降低肿瘤球形成能力(P<0.05),而自噬抑制剂3-MA处理不能逆转rapamycin的效应。结论:mTOR信号通路能够调控胶质瘤干细胞自我更新,阻断mTOR通路下调胶质瘤干细胞自我更新潜能。BACKGROUND OBJECTIVE：Activation of mammalian target of rapamycin（mTOR）has been associated to poor prognosis of glioma patients.This study was designed to investigate the regulatory mechanisms of mTOR signaling on self-renewal of glioma stem cells（GSCs）.METHODS：CD133＋GSCs have been isolated by using CD133 magnetic beads from human glioblastoma specimens and glioma cell line SKMG-4 and were propagated without serum in vitro.Molecular markers for glioma stem cells（CD133,nestin,Sox-2,GFAP and TuJ1） were detected by immunofluorescent staining.mTOR signaling passway was inactivated by rapamycin treatment.Self-renewal was tested by tumor sphere formation assay.The phosphorylation status of mTOR components was determined by Western blot analysis.All statistical analyses were performed using the SPSS software package,version11.0.RESULTS：The levels of p-S6K and p-S6,components of mTOR signaling,were higher in CD133＋GSCs than matched CD133-cells.GSC fractions also expressed high levels of Bmi-1,a key regulator of neural stem cell self-renewal.Inhibition of the mTOR signaling pathway by rapamycin resulted in a reduction of.tumor sphere formation,which is indenpendent from autophagy since 3-MA did not revise the effect of rapamycin.Rapamycin treatment also resulted in differentiation of the CD133＋GSCs.CONCLUSION：Disruption of mTOR signals can impair stem cell selfrenewalandconcomitantly trigger lineage differentiation.

关 键 词：胶质瘤干细胞 MTOR信号通路 自我更新 

分 类 号：R739.41[医药卫生—肿瘤]