下调XBP1基因表达对脑胶质瘤细胞活力和凋亡的影响

Effect of down-regulation of X-box binding protein 1 gene expression on viability and apoptosis of glioma cells

目的:探讨下调X盒结合蛋白1(XBP1)表达对脑胶质瘤细胞活力和凋亡的影响。方法:q PCR检测脑胶质瘤组织中XBP1的m RNA表达。将干扰XBP1表达的小干扰RNA(XBP1-si RNA组)转染人脑胶质瘤U251细胞,同时设置正常对照(control)组(细胞无特殊处理)和阴性对照(NC-si RNA)组(转染不具有任何干扰作用的si RNA),转染48 h后,用q PCR检测3组细胞中XBP1的m RNA表达;Western blot检测XBP1、增殖细胞核抗原(PCNA)、B细胞淋巴瘤/白血病-2(Bcl-2)、Bcl-2相关X蛋白(Bax)、细胞周期素D1(cyclin D1)、磷脂酰肌醇3-激酶(PI3K)和磷酸化Akt(p-Akt)蛋白水平;CCK-8法检测细胞活力;流式细胞术检测细胞周期及凋亡。结果:XBP1在脑胶质瘤中的表达显著高于瘤旁组织(P<0.05);转染XBP1-si RNA后,细胞中XBP1的m RNA及蛋白表达均显著降低(P<0.05);NC-si RNA组细胞活力、细胞周期变化、细胞凋亡率及PCNA、Bcl-2、Bax、cyclin D1、PI3K和p-Akt的蛋白水平与control组比较差异无统计学显著性;XBP1-si RNA组细胞活力、S期细胞及PCNA、Bcl-2、cyclin D1、PI3K和p-Akt蛋白水平均显著低于control组,细胞凋亡率、G0/G1期细胞及Bax蛋白表达均显著高于control组(P<0.05)。结论:下调脑胶质瘤细胞XBP1基因表达可降低肿瘤细胞的活力,阻滞细胞于G1期,并促进细胞的凋亡,其机制可能与抑制PI3K/Akt信号通路有关。

AIM:To investigate the effect of down-regulation of X-box binding protein 1(XBP1)expression on the viability and apoptosis of glioma cells.METHODS:The mRNA expression of XBP1 in the glioma tissues was detected by qPCR.Small interfering RNA(siRNA)interfering with XBP1 expression(XBP1-siRNA)was transfected into human brain glioma U251 cells.At the same time,control group(the cells without special treatment)and negative control(NC-siRNA)group(transfected with siRNA without any interference)were set up.The mRNA expression of XBP1 in the 3 groups 48 h after transfection was detected by qPCR.The protein levels of XBP1,proliferating cell nuclear antigen(PCNA),B-cell lymphoma/leukemia-2(Bcl-2),Bcl-2-associated X protein(Bax),cyclin D1(cyclin D1),phosphatidylinositol 3-kinase(PI3K)and phosphorylated Akt(p-Akt)were determined by Western blot.The cell viability was measured by CCK-8 assay.The cell cycle distribution and apoptosis were analyzed by flow cytometry.RESULTS:The expression level of XBP1 in the glioma tissues was significantly higher than that in the tumor adjacent tissues(P<0.05).The XBP1 expression at mRNA and protein levels was significantly decreased in the cells transfected with XBP1-siRNA(P<0.05).No statistically significant difference of the cell viability,cell cycle,apoptotic rate and the protein levels of PCNA,Bcl-2,Bax,cyclin D1,PI3K and p-Akt between NC-siRNA group and control group was observed.Compared with control group,the cell viability,S-phase cells and the protein levels of PCNA,Bcl-2,cyclin D1,PI3K,and p-Akt in XBP1-siRNA group were decreased significantly,and the apoptotic rate,G 0/G 1-phase cells and Bax protein expression were significantly increased(P<0.05).CONCLUSION:Down-regulation of XBP1 gene expression in brain glioma cells reduces the viability of cancer cells,blocks the cells in G 1 phase and promote apoptosis.The mechanism is related to the inhibition of PI3K/Akt signaling pathway.