【摘要】 背景与目的:EB病毒潜伏膜蛋白(latentmembraneprotein1,LMP1)是被证实在鼻咽癌中具有癌基因功能的病毒编码基因的表达产物;LMP1参与异常的细胞周期调控,但是否导致有丝分裂检测点调控机制紊乱仍未得到实验证实。本实验观察LMP1对鼻咽癌细胞株CNE1有丝分裂调控的影响,进一步探讨LMP1在鼻咽癌发病机制中的作用。方法:用流式细胞仪观察CNE1(人高分化鼻咽癌细胞株,即WHO分型的角化性鳞状细胞癌)、CNE1-GL(转染目的基因质粒PAT-GFP-LMP1的CNE1细胞株)和CNE-2Z(人低分化鼻咽癌细胞株,即WHO分型的分化型非角化性癌)的周期分布和LMP1对CNE1有丝分裂检测点功能的影响;用Westernblot方法检测P34cdc2、CyclinB1和P53蛋白表达的变化。结果:CNE1-GL组G2/M期细胞显著升高(P<0.05),但增殖指数(proliferationindex,PI)变化不明显。CNE1-GL细胞株有丝分裂检测点功能存在一定缺陷,细胞发生“有丝分裂滑移”。CNE1-GL细胞中P34cdc2和CyclinB1表达分别为CNE1的(1.22±0.04)倍和(2.12±0.07)倍,但P53蛋白的变化不明显(P>0.05)。结论:LMP1通过诱导P34cdc2、CyclinB1的上调性表达,影响CNE1细胞株的周期分布和有丝分裂检测点的功能。更多还原

【Abstract】 BACKGROUND &OBJECTIVE: Epstein Barr virus (EBV) latent membrane protein 1(LMP1)is the only one of approved oncogene coded by virus gene in nasopharyngeal carcinoma (NPC). LMP1 is involved in the regulation of cell cycle but it is still unknown if LMP1 induces the disturbance of mitosis control and mitotic checkpoint. The aim of this study was to investigate the effect of EBV LMP1 on mitosis control of NPC cell line CNE1 and the related pathogenesis of NPC. METHODS: Cell cycle and the function of mitotic checkpoint were assayed by flow cytometry in human NPC cells cultured in vitro, including CNE1 cell line (well differentiated cells of NPC, WHO classified it as keratinizing squamous cell carcinoma), CNE1 GL cell strain (CNE1 cell line transfected with an eukaryotic plasmid PAT GFP LMP1) and CNE 2Z cell line (poorly differentiated cells of NPC, WHO classified it as differentiated non keratinizing carcinoma). Before investigating expression of proteins, the cells were synchronized at mitosis phase. The expression of mitotic regulators, P34cdc2, cyclin B1, and p53 was subsequently determined using Western blot analysis. RESULTS: The G2/M ratio of CNE1 GL was significantly elevated compared with CNE1 (P< 0.05). A defective mitotic checkpoint was identified in CNE1 GL, and this phenomenon was also known as “mitotic slippage”. Western blot analysis showed that the expression levels of P34cdc2 and cyclin B1 proteins in CNE1 GL were 1.22±0.04 and 2.12±0.07 times higher than that of those in CNE1, respectively,but there was no difference in the expression of p53 protein between CNE1 GL and CNE1. CONCLUSION: LMP1 disturbs mitosis control and the function of mitotic checkpoint of CNE1 through up regulating the expression of P34cdc2 and cyclinB1 proteins.更多还原