中文摘要：

目的：探讨小干扰RNA（small interfering RNA，siRNA）抑制TP53诱导的糖酵解和凋亡调节因子（TP53-induced glycolysis and apoptosis regulator，TIGAR）表达后对肺腺癌A549细胞化疗敏感性的影响及其可能的作用机制。方法：化学合成针对丁，G4尺基因的特异性siRNA片段（siRNA-TIGAR）和对照干扰片段（siRNA—control）。将siRNA-TIGAR或siRNA—control转染至A549细胞后，应用实时荧光定量-PCR和蛋白质印迹法检测细胞中TIGAR mRNA及蛋白的表达，CCK-8（cell counting kit-8）法检测依托泊苷、5-氟尿嘧啶、顺铂、依托泊苷联合N-乙酰-L-半胱氨酸和H2O2作用后细胞的存活率，FCM法检测H2O2作用后细胞的凋亡率及细胞内活性氧（reactive oxygen species，ROS）水平。结果：siRNA-TIGAR转染组A549细胞中TIGAR mRNA及蛋白的表达水平明显下降（P〈0．01）；依托泊苷、5-氟尿嘧啶和顺铂对siRNA-TIGAR转染组A549细胞的半数抑制浓度（half inhibitory concentration，IC50）明显降低（P〈0．05）；H2O2作用后，siRNA-TIGAR转染组A549细胞的存活率下降、凋亡率和细胞内ROS水平上升（P〈0．05）；依托泊苷联合N-乙酰-L-半胱氨酸作用后，siRNA-TIGAR转染组和siRNA—control转染组A549细胞对依托泊苷敏感性之间的差异无统计学意义（P〉0．05）。结论：抑制TIGAR的表达可以增强A549细胞对化疗药物的敏感性，其机制可能与细胞内ROS水平的改变有关。

英文摘要：

Objective： To investigate the effect of inhibition of TP53-induced glycolysis and apoptosis regulator （TIGAR） expression by small interfering RNA （siRNA） on sensitivity to chemotherapy in A549 lung adenocarcinoma cells and its possible mechanism. Methods： siRNA targeting TIGAR gene （siRNA- TIGAR） and the control siRNA （siRNA-control） were chemically synthesized. After transfection with siRNA- TIGAR or siRNA-control in A549 cells, the expression levels of TIGAR mRNA and protein were detected by real-time fluorescence quantitative-PCR and Western blotting, respectively. The cell viability of A549 cells transfected with siRNA-TIGAR or siRNA-control and treated with etoposide, 5-fluorouracil, cis- dichlorodiamineplatinum or etoposide in combination with N-acetyl-L-cysteine and H2O2 was examined by cell counting kit-8 （CCK-8） assay. The apoptotic rate and the reactive oxygen species （ROS） level in A549 cells were detected by flow cytometry （FCM）. Results： The expression levels of TiGAR mRNA and protein in A549 cells transfected with siRNA-TIGAR were obviously decreased （P 〈 0.01）. The half inhibitory concentration （IC50）values of etoposide, 5-fluorouracil and cis-dichlorodiamineplatinum for A549 cells transfected with siRNA-TIGAR were significantly reduced （P 〈 0.05）. After treatment with H2O2, the cell viability of A549 cells transfected with siRNA-TIGAR was decreased, while the apoptotic rate and the intracellular ROS level were increased （both P 〈 0.05）. After treatment with etoposide in combination with N-acetyl-L-cysteine, there was no significant difference in sensitivity to etoposide in A549 cells between siRNA-TIGAR group and siRNA-control group （P 〉 0.05）. Conclusion： The sensitivity to chemotherapy in A549 cells can be enhanced by inhibiting the expression of TIGAR. This effect may be related to the change of intracellular ROS level.