Caveolin-1对胃癌细胞系MGC803细胞生长的影响

Effect of Caveolin-1 on growth of human gastric cancer cell Line MGC803

目的:研究Caveolin-1对胃癌细胞增殖、分化的影响,以探讨Caveolin-1作为基因治疗的候选基因的可能性．方法:运用基因重组技术,将人全长 Caveolin-1基因稳定转染胃癌细胞系MGC803．建立能稳定表达Caveolin-1的胃癌细胞系．同时建立空载体转染的MGC803细胞系作为空白对照,另用PD98059处理48 h作为阳性对照．以重组细胞系作为研究模型,通过免疫细胞化学及Western blot确认Caveolin-1蛋白在被转染细胞中的稳定表达．运用光学显微镜观察转染前后MGC803细胞形态的变化;另运用细胞计数检测了Caveolin-1对MGC803细胞生长的影响,流式细胞术分析了Caveolin-1对MGC803 细胞周期分布的影响．结果:Western blot结果显示,基因转染组及阳性对照组细胞中Vaveolin-1表达比未处理组细胞中明显增强(P<0．001,q值分别为23．067 与13.3376),且基因转染组中Caveolin-1表达比阳性对照组更强(P<0．00l,q=9．7294);基因转染后的MGC803细胞形态发生明显变化,由异形性明显、核大、胞质很少、核分裂明显变得形态较一致、胞质丰富、核／质比明显变小、核分裂相很少见;基因转染后细胞的群体倍增时间明显延长,由46．67 h延长至65．46 h,差异有统计学意义(P<0．05,q =4．8695):基因转染后细胞周期分布发生了明显变化,G0／G1期细胞数明显增多(P<0．01, q=9．1824),S期细胞数明显减少(P<0．01,q= 7．827),G2／M期细胞数无明显变化(P>0．05), Caveolin-1基因转染组与阳性对照组间细胞周期分布的变化也有明显差异性(其中G0／G1期 P<0．01,q=4．9323;S期P<0．05,q=3．3295)．结论:Caveolin-1既能诱导MGC803细胞分化又能将其阻滞于G0/G1期,通过延长细胞群体倍增时间而抑制胃癌细胞的体外增殖．

AIM： To investigate the effect of Caveolin-1 on the proliferation and differentiation of gastric carcinoma cell line MGC803, and explore the probability that Caveolin-1 can be used for gene therapy. METHODS： Caveolin-1 gene and Pcl-neo control plasmid were transfected into human MGC803 cell line by lipofectin, respectively. The positive clones were selected by G418. We also stabled a positive control group which was treated with PD98059 for 48 hours. Then the expression of Caveolin-1 in each group was detected by Westem blot. Cell morphology was observed under optical microscope. Cell population doubling time was determined by cell counting method and cell cycle was analyzed by flow cytometry. RESULTS： The expression of Caveolin-1 was significantly higher in the cells treated with Caveolin-1 or PD98059 than that in the empty controls （P 〈 0.001, q = 23.067 or 13.3376）. Furthermore, Caveolin-1 expression was also markedly higher in the cells transfected with Caveolin-1 than that in the positive controls （P 〈 0.001, q = 9.7294）. Under light microscope, marked changes occurred in cell morphous after gene transfection. Before transfection, the cells had a significant heteromorphism, with the fea- tures of large cell body, little cytoplasm, obvious karyokinesis. While in Caveolin-1-transfected MGC803 cells, the cell malignancy declined as the cellular heteromorphism diminished, with the ratio of nuclear-to-cytoplasm decreased, and the karyokinesis disappeared. Caveolin-1-transfected cells had an extended doubling time （65.46 h vs 46.67 h, P 〈 0.05, q = 4.8695）. At same time, the population of Caveolin-1-transfected cells in G0/G1 phase was obviously increased （P 〈 0.01, q = 9.1824） while that in S phase was decreased （P 〈 0.01, q = 7.827）. There were also notable differences in cell cycle distribution between Cave- olin-1-transfected cells and the positive controls （G0/G1： P 〈 0.01, q = 4.9323; S： P 〈 0.05, q = 3.3295）. CONCLUSION： Caveolin-1 not only induces the differentiation of MGC803 cells, but also blocks them at in G0/G1 phase. Caveolin-1 can inhibit the proliferation of MGC803 cells in vitro by prolonging the cell doubling time.