BTG2基因对胃癌细胞系生物学特性影响的研究

目的:初步探讨细胞增殖抑制基因BTG2对于胃癌细胞生长、增殖状态、细胞周期和凋亡状态等生物学特性及成瘤、侵袭转移能力等恶性表型的影响。方法:将BTG2基因插入载体PCD-NA3.1构建PC-BTG2真核表达载体。以脂质体介导转染MKN45胃癌细胞,经G418压力筛选法筛出稳定表达的阳性克隆,经流式细胞仪、生长曲线法、平板克隆形成和细胞迁徙等实验分析稳定表达株相关生物学特性变化,每种检测实验均设立PC-BTG2稳定转染细胞组、PCDNA3.1稳定转染细胞组和空白MKN45细胞组。结果:与转染PCDNA3.1空载体及空白MKN45胃癌细胞相比:1)转染PC-BTG2载体的稳定表达细胞株生长速度提高,开始计数后第3、4、5、6和7天PC-BTG2转染组平均细胞计数均显著低于其他两组,F=350.83,P<0.05;2)细胞周期检测显示,PC-BTG2转染组G0～G1期比例显著高于其他两组,F=18.70,P<0.05,而G2～M(F=35.36)、S期(F=20.94)比例显著低于其他两组,P<0.05;3)细胞凋亡检测显示,PC-BTG2转染组凋亡比例显著高于其他两组,F=37.34,P<0.05;4)平板克隆形成实验结果显示,PC-BTG2转染组平均克隆形成率显著低于其他两组,F=54.3,P<0.05;5)细胞迁徙实验结果提示,PC-BTG2转染组穿膜率显著低于其他两组,F=46.1,P<0.05。结论:BTG2基因有较显著的抑制细胞生长增殖作用,同时可影响细胞周期,减少分裂期细胞,促进细胞凋亡,并具有降低肿瘤细胞侵袭转移能力的作用。

Study on functions of BTG2 in gastric cancer cell lines

OBJECTIVE:To investigate the influence of BTG2 on the growth, proliferation, apoptosis, infiltration and cell cycle of gastric cancer line MKN45. METHODS: A critical antiproliferative gene, BTG2 cDNA was subcloned into a constitutive vector PCDNA3.1 followed by transfection in MKN45 by using liposome. Then stable expression clones were selected and appraised. The apoptosis and cell cycles were detected by using flow cytometry. The growth and proliferation were analyzed by making cell growth curves and the colony formation assay, respectively. The ability of infiltration was tested by the cancer cell migration assay. The MKN-BTG2 group and two control groups were detected. RESULTS: 1) MKN-BTG2 grew slower than MKN45 and MKN-PC. The cell counts of MKN-BTG2 in the third, forth, fifth, sixth and seventh days were significantly fewer than those of the others, F=350.83, P<0.05. 2)The cell cycle analysis showed that proportions of cells in G0-G1, stages in PC-BTG2 group were higher than the other two groups significantly(F=18.70, P<0.05) which were lower in G2-M(F=35.36) and S(F=20.94), P<0.05. 3)The inhibitory proportion of PC-BTG2 group was higher than that of the other two groups, F=37.34, P<0.05; 4)The results of the colony formation assay showed that the colony formation rate of MKN-BTG2 was lower than that of the control groups, F=54.3, P<0.05. 5)The results of the cell migration assay suggested that the cell migration rate of MKN-BTG2 was lower than that of the control groups, F=46.1, P<0.05. CONCLUSIONS: BTG2 can restrain the growth and proliferation of gastric cancer cells and restrict tumor cells, to maintain the malignant phenotype. Furthermore, it can restrict infiltration and metastasis of gastric cancer cells.