目的：研究凋亡抑制Livin对肺腺癌细胞A549增殖与耐药的作用。方法通过脂质体将真核表达载体pcDNA3.1⁃Livin转染至人肺腺癌细胞A549中，经过G418筛选获得稳定表达Livin的A549细胞克隆；采用RT⁃PCR和Western blot法检测Livin在转染细胞中基因和蛋白的表达，通过流式细胞仪分析细胞周期的分布，应用MTT比色法检测细胞在不同化疗药物作用下的细胞耐药性，并通过RT⁃PCR和Western blot法检测转染细胞中P⁃糖蛋白（P⁃gp）基因和蛋白的表达。结果在pcDNA3.1⁃Livin转染后的A549细胞中，Livin基因的mRNA和蛋白表达显著增加，G0/G1期细胞比例降低，而S期细胞比例增高；与对照组比较，转染pcDNA3.1⁃Livin的A549细胞中P⁃gp基因的表达明显增高，对ADM、MTX、CTX和DDP等多种化疗药物的耐药性也明显增强（P<0.05）。结论 Livin基因的表达升高能增强肺腺癌细胞A549的增殖能力，并且可以通过增加P⁃gp的表达降低细胞对多种化疗药物的敏感性。%Objective To study the effect of the inhibitor of apoptosis protein,Livin on proliferation and multi⁃drug resistance of lung adenocarcino⁃ma cells A549. Methods A549 cells were transfected with the eukaryotic expression vector pcDNA3.1⁃Livin. A549 cell clone with stable expres⁃sion of Livin was obtained through G418 screening. Expressions of Livin mRNA and protein in the transfected cells were respectively measured by re⁃verse transcription polymerase chain reaction(RT⁃PCR)and Western blot. The distribution of cell cycle phase was determined using flow cytometry. The level of P⁃gp mRNA and protein in A549 cells transfected with pcDNA3.1⁃Livin was detected by RT⁃PCR and Western blot. The analysis of multi⁃drug resistance of A549 treated with different chemotherapeutics was performed by MTT. Results The mRNA and protein expressions of Liv⁃in were both significantly increased in the transfected A549 cells. The flow cytometry analysis showed there was higher percentage of S phase and low⁃er percentage of G0/G1 phase in A549 cells transfected with pcDNA3.1⁃Livin. Compared with control groups,the expression of P⁃gp mRNA and pro⁃tein was increased in A549 cells transfected with pcDNA3.1⁃Livin,which showed a higher drug resistance and lower sensitivity to chemotherapic drugs such as ADM,MTX,CTX,and DDP(P<0.05). Conclusion Overexpression of Livin could enhance the proliferation of A549 cells,and high expression of P⁃gp caused by Livin could serve as one of the causes for multi⁃drug resistance in lung adenocarcinoma against chemotherapies.
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