PP2A对转化生长因子β_1诱导的淋巴瘤细胞凋亡的影响  

PP2A-dependent Apoptotic Effect of Exogenous Transforming Growth Factor-β_1 on Human Burkitt's Lymphoma Cell Line Raji Cells and Its Mechanism

作　　者：赵哲[1] 刘莉[1] 刘琨[1] 姚平[1] 汪茂荣[1] 

机构地区：[1]湖北民族学院附属民大医院血液内科,恩施445000

出　　处：《华中科技大学学报（医学版）》2017年第1期55-59,共5页Acta Medicinae Universitatis Scientiae et Technologiae Huazhong

基　　金：湖北省教育厅科研项目(No.B2015101)

摘　　要：目的探讨转化生长因子β_1(TGF-β_1)诱导B细胞淋巴瘤细胞株Raji细胞凋亡的效应及机制。方法采用TGF-β_1(5 ng/mL)刺激Raji细胞,流式细胞术检测0、24、48、72 h细胞凋亡情况;定量PCR法检测Bcl-2、Bcl-xl、Caspase-3 mRNA表达;Western blot法检测Bcl-2,Bcl-xl以及Caspase-3蛋白表达及细胞外信号调节激酶ERK1/2磷酸化情况;蛋白磷酸酶活性测定体系检测TGF-β_1刺激下蛋白磷酸酶2A(PP2A)活性变化;观察不同浓度PP2A抑制剂冈田酸(okadaic acid,OA)对TGF-β_1诱导的细胞凋亡的干预效应。结果 5 ng/mL TGF-β_1刺激24、48、72 h后细胞凋亡率分别为(29±3)%、(47±4)%、(60±5)%,差异有统计学意义(均P<0.05);同时,随着刺激时间延长,Bcl-2、Bcl-xl mRNA和蛋白表达逐渐降低,Caspase-3 mRNA和蛋白表达逐渐增加,差异有统计学意义(均P<0.05);ERK1/2总蛋白表达无显著差异,其磷酸化状态p-ERK1/2随TGF-β_1刺激时间的延长逐渐减少;PP2A活性在TGF-β_1干预15 min后开始升高,1 h达峰值;100、200 nmol/L的OA分别预处理后细胞凋亡率明显下降,TGF-β_1组为(60±5)%,干预组分别为(32±4)%、(24±3)%,差异有统计学意义(均P<0.05)。结论 TGF-β_1可能通过活化PP2A、抑制ERK1/2通路相关基因的表达而诱导B细胞淋巴瘤Raji细胞凋亡。Objective To study the apoptotic effect of exogenous TGF-β1 on human Burkitt＇s lymphoma cell line Raji cells and its mechanism.Methods Raji cells were treated with recombinant TGF-β1 at different concentrations（0,1,5,10 ng/mL）or stimulated by TGF-β1 for different time（0,24,48,72 h）.The apoptosis rate of Raji cells was detected by flow cytometry.Gene expression levels of Bcl-2,Bcl-xl and Caspase-3 were assayed by real-time PCR.Western blot analysis was used to assay the protein expression level of Bcl-2,Bcl-xl,Caspase-3,ERK1/2 and p-ERK1/2.Protein Ser/Thr phosphatase activity was assayed photometrically using the Serine/Threonine Phosphatase Assay System according to the manufacturers directions.Results Cell apoptosis rate was（29±3）%,（47±4）%and（60±5）%,24,48 and 72 h after stimulation of 5 ng/mL TGF-β1（all P〈0.05）.Simultaneously,mRNA and protein expression levels of Bcl-2 and Bcl-xl were decreased,and those of Casepase-3 were increased with time.Total protein expression of ERK1/2 was not significantly different,but p-ERK1/2 was decreased with TGF-fSi stimulation.After pretreatment of 100 and 200 nmol/L okadaic acid（OA）,cell apoptosis rate was significantly decreased[（60 ± 5）%vs.（32±4）%and（24±3）%;both P〈0.05].Conclusion TGF-β1 induces Raji cell apoptosis by the activation of PP2 A and down-regulation of ERKl/2 signal pathway related genes.

关 键 词：转化生长因子Β1 伯基特淋巴瘤 细胞凋亡 蛋白磷酸酶2A 

分 类 号：R733.4[医药卫生—肿瘤]