EB病毒LMP1对人鼻咽癌细胞转移能力的影响

Effects of Epstein-Barr Virus Latent Membrane Protein 1 on Metastasis of Human Nasopharyngeal Carcinoma Cell Lines

背景与目的:EB病毒编码的潜伏膜蛋白1(latent membrane protein 1,LMP1)在鼻咽癌的浸润和转移过程中起重要的作用。本实验目的在于研究EB病毒LMP1对人鼻咽癌细胞转移能力的影响和探讨其中的相关机制。方法:应用免疫细胞化学RT-PCR法和Western blot检测LMP1、E-cadherin和intercellular adhesion molecule-1 (ICAM-1)在人高分化鼻咽癌细胞系CNE1和转染了LMP1基因的CNE1-GL细胞中的表达。应用细胞-细胞粘附实验、细胞-基质粘附实验、划痕实验和细胞运动实验观察LMP1对鼻咽癌细胞粘附和运动能力的影响。结果:免疫细胞化学结果显示:LMP1在CNE1和CNE1-GL细胞中的阳性率分别为0和(96.60±3.03)%(P<0.01);E-cadherin蛋白的阳性率分别为(37.47±1.50)%和(19.53±1.92)%(P<0.01);ICAM-1蛋白的阳性率分别为(5.27±1.45)%和(93.33±4.23)%(P<0.01)。RT-PCR和Westernblot结果表明,与CNE1细胞相比较,CNE1-GL细胞中E-cadherin的mRNA和蛋白表达明显降低(P<0.01),而ICAM-1的mRNA和蛋白表达则明显升高(P<0.01)。肿瘤细胞同质粘附实验显示,CNE1-GL细胞的同质粘附能力较CNE1细胞弱(P<0.05)。肿瘤细胞-基质粘附实验得出CNE1-GL细胞的异质粘附能力(A值=0.60±0.03)较CNE1细胞(A值=0.46±0.01)强(P<0.01)。肿瘤细胞运动实验显示,穿过PVPF膜的CNE1-GL细胞数多于CNE1细胞(119.3±6.0 vs 46.3±7.0,P<0.05)。结论:LMP1通过抑制E-cadherin表达、促进ICAM-1表达从而抑制肿瘤细胞的同质粘附能力、增强其异质粘附能力和运动能力来参与鼻咽癌的侵袭和转移。

BACKGROUND ＆ OBJECTIVE： Epstein-Barr virus （EBV）- encoded latent membrane protein 1 （LMP1） plays an important role in the metastasis of nasopharyngeal carcinoma （NPC）. This study was to investigate the effects of EBV LMP1 on the metastasis of NPC celt lines, and explore potential mechanism. METHODS： The expression of LMP1, E- cadherin and intercellular adhesion molecule-1 （ICAM-1） in human NPC cell lines CNE1 （well differentiated） and CNE1-GL （CNE1 cells transfected with LMP1） were detected by SP immunohistochemistry, reverse transcription- polymerase chain reaction （RT-PCR） and Western blot. The cell-cell adhesion assay, the cell-matrix adhesion assay, the wound-induced migration assay and the migration assay were used to investigate the effects of LMP1 on adhesive and metastatic abilities of NPC cells. RESULTS. The positive rates of LMP1 and ICAM-1 were significantly lower in CNE1 cells than in CNE1-GL cells [0% vs. （96.60±3.03）%, P〈0.01; （5.27±1.45）% vs. （93.33±4.23）%, P〈0.01]; the positive rate of E-cadherin was significantly higher in CNE1 cells than in CNE1-GL cells [（37.47±1.50）% vs. （19.53± 1.92）%, P〈0.01]. The expression of E-cadherin was significantly inhibited （P〈0.01）, while the expression of ICAM-1 was significantly increased （P〈 0.01） in CNE1-GL cells as compared with those in CNE1 cells. The cell-cell adhesive ability of CNE1-GL cells was lower than that of CNE1 cells （P〈 0.05）. The cell-matrix adhesive ability of CNE1-GL cells was significantly higher than that of CNE1 cells （0.60±0.03 vs. 0.46±0.01, P〈0.01）. The number of migrated CNE1-GL cells was higher than that of migrated CNE1 cells （119.3±6.0 vs. 46.3±7.0, P〈0.05）. CONCLUSION： By inhibiting E- cadherin expression and enhancing ICAM-1 expression, LMP1 may reduce the cell-cell adhesive ability and improve the cell-matrix adhesive ability and migratory ability of NPC cells, which may play roles in the invasion and metastasis of NPC.