eIF5A1对非小细胞肺癌细胞系化疗药物敏感性的影响

目的:探讨eIF5A1对非小细胞肺癌（non-small cell lung cancer，NSCLC)细胞系化疗药物敏感性的影响及可能的机制。方法:应用RT-PCR法检测不同NSCLC细胞系eIF5A1 mRNA表达水平。MTT法检测其对吉西他滨的敏感性，并分析二者的关系。构建真核表达载体pEGFP-C1-eIF5A1并通过脂质体介导法转染肺腺癌LTEP-a-2 细胞。荧光显微镜、RT-PCR和Western blot方法评估转染效率。MTT法检测转染后细胞化疗药物敏感性变化。流式细胞仪检测转染后细胞周期及凋亡变化。结果:肺鳞癌细胞系eIF5A1 mRNA表达水平及对吉西他滨的敏感性均显著高于肺腺癌细胞系（P<0.001）。pEGFP-C1-eIF5A1转染eIF5A1表达水平最低的LTEP-a-2细胞后eIF5A1 mRNA及蛋白表达水平显著升高（P<0.001）。与对照组细胞比较，eIF5A1转染组细胞对吉西他滨、顺铂、紫杉醇、多西紫杉醇的敏感性显著增加（P<0.001）。S期和G2/M期细胞比例显著增加（P<0.001）。在化疗药物作用下，细胞凋亡率显著增加（P<0.001）。结论:在非小细胞肺癌中上调eIF5A1的表达可能增加细胞对化疗药物的敏感性，其机制可能与eIF5A1高表达增强化疗药物的促凋亡作用及影响细胞周期分布有关。

Effect of eIF5A1 gene on chemosensitivity of human NSCLC cell lines

Objective:To investigate the effect of eIF5A1 gene on chemosensitivity of human NSCLC cell lines and the possible mechanism.Methods:Expression levels of eIF5A1 mRNA in different NSCLC cell lines were measured by RT-PCR .The sensitivities to gemcitabine for cells were detected by MTT assay.The correlation between the above two was analysized.The eukaryotic expression plasmid pEGFP-C1-eIF5A1 was constructed and transfected into the LTEP-a-2 cells by liposome transfection reagent.The transfection was proved effective by the fluorescence microscopy，RT-PCR and Western blot.MTT assay was used to investigate the effects of eIF5A1 overexpression on the drug sensitivities of LTEP-a-2 cells.The change of apoptosis rate and cell cycle were detected by flow cytometry （FCM).Results:Lung squamous cell lines had higher eIF5A1 expression levels and sensitvities to gemcitabine than adencarcinoma cell lines （P<0.001）.eIF5A1 mRNA and protein expression levels of LTEP-a-2 cell line with the lowest eIF5A1 expression level were significantly increased after transfection with pEGFP-C1-eIF5A1 （P<0.001）.Compaired with the empty vector group or un-transfected group，the sestivities to cisplatin，gemcitabine，paclitaxel，docetaxel were significantly increased for eIF5A1 gene transfected group （P<0.001），inforced eIF5A1 expression increased the cell cycle arrest in S and G2/M phase （P<0.001）.With the treatment of chemotherapeutic agents，the cell apoptosis also significantly increased in the eIF5A1 gene transfected group （P<0.001）.Conclusion:Overexpression of eIF5A1 in non-small cell lung cancer may increase the sensitivity of cells to chemotherapeutic agents.eIF5A1 may influence chemosensitivity of non-small cell lung cancer through promoting apoptosis-accelerating effects of chemotherapeutic agents and changing the cell cycle.