中文摘要：

探讨微小RNA-21（miR-21）在增强人脑胶质瘤细胞对卡莫司汀（BCNU）耐药中的作用及其可能的作用机制。方法：用jetPRIME将miR-21mimics及阴性对照序列转入人脑胶质瘤细胞SWOZ2，用实时荧光定量PCR法检测BCNU敏感株SWOZ2与BCNU耐药株SWOZ2-BCNU、SWOZ2-miR-21mimics细胞与对照组细胞中miR-21表达差异，用CCK-8检测这两对细胞对BCNU敏感度的差异，用Westernblotting检测这两对细胞中第10号染色体同源缺失性磷酸酶及张力蛋白（PTEN）、磷酸化蛋白激酶B（P—Akt）和P-糖蛋白（P—gP）表达的差异。结果：SWOZ2-BCNU细胞miR-21的表达水平明显高于SWOZ2细胞，转染组SWOZ2-miR-21mim—ics细胞中miR-21的表达量明显高于对照组；SWOZ2-BCNU细胞BCNU的半数抑制浓度（Ic50）明显高于SWOZ2细胞，转染组细胞BCNU的Ic。明显高于对照组；与SWOZ2细胞相比，SWOZ2-BCNU细胞中PTEN蛋白的表达明显降低，P—Akt和P—gp蛋白的表达都明显升高；转染后，与对照组相比，转染组细胞中PTEN蛋白的表达明显降低，而P—Akt和P—gP蛋白的表达皆明显升高。结论：miR-21可能通过下调PTEN蛋白表达，增强人脑胶质瘤细胞对BCNU耐药。

英文摘要：

AIM： To explore the function of miR - 21 in human glioma cells resistant to carmustine[ 1,3 - bis （2 -chloroethyl） -1 -nitrosourea, BCNU ] and to elucidate its related mechanism. METHODS： SWOZ2 cells were transfected with miR -21 mimics （SWOZ2 -miR -21 mimics） or miRNA mimics negative control （control group） by the method of jetPRIME. The real - time fluorescence quantitative PCR was used to detect and compare the levels of miR - 21 expression between BCNU - resistant cell line SWOZ2 - BCNU and BCNU - sensitive cell line SWOZ2, or between SWOZ2 - miR - 21 mimic group and control group. The drug sensitivity of these cells to BCNU was determined by CCK - 8 assay. The protein expression of phosphatase and tensin homology deleted on chromosome 10 （PTEN）, phosphorylated protein ki- nase B （p- Akt） and P- glycoprotein （P- gp） in these cells were also detected by Western blotting. RESULTS： The expression level of miR - 21 was remarkably higher in SWOZ2 - BCNU cells than that in SWOZ2 cells. The expression lev- el of miR-21 was significantly higher in SWOZ2 -miR-21 mimics group than that in control group. The half- maximal inhibitory concentration （ICw ） of BCNU was obviously higher for SWOZ2 - BCNU cells than that for SWOZ2 ceils. The ICso of BCNU was markedly higher in SWOZ2 - miR - 21 mimics group than that in control group. PTEN protein expression was remarkably lower, but p - Akt and P - gp protein expression levels were markedly higher in SWOZ2 - BCNU cells than those in SWOZ2 cells. The protein level of PTEN was significantly lower, but the protein levels of p - Akt or P - gp were distinctly higher in SWOZ2 -miR -21 mimics group than those in control group. CONCLUSION： miR -21 enhances the resistance of human glioma cells to BCNU by down - regulating the expression of PTEN protein.