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目的研究G型细胞周期蛋白(cyclin)家族中的新成员cyclinG2在胃癌组织中的表达和其对胃癌细胞株SGC7901体外增殖的影响。方法通过免疫组织化学技术检测40例胃癌标本中cyclinG2蛋白的表达情况并进行显微图像分析;利用阳离子介导的脂质体转染试剂将包含有cyclinG2的真核表达载体pIRESG2转染SGC7901,经G418克隆筛选后获得稳定表达cyclinG2的细胞克隆,噻唑蓝法(MTT)比色法测定转染后细胞增殖活性的改变。结果①CyclinG2在非癌组织、分化型癌和差分化型癌组织中的阳性率和表达强度逐渐下降且差异有统计学意义(P<0.01)。②转染pIRESG2获得的克隆细胞的体外增殖能力降低(P<0.01)。结论CyclinG2基因很可能是一种候选的抑癌基因,随着胃癌恶性程度的增加其表达水平降低;外源性基因转染导致的cyclinG2异常性高表达可显著抑制胃癌细胞株的体外增殖能力。
Objective To study the expression of cyclinG2, a novel member of cyclin family, in gastric cancer and its effect on the proliferation of gastric cancer cell line SGC7901 in vitro. Methods The expression of cyclinG2 in 40 gastric cancer specimens was detected by immunohistochemistry and analyzed by microscopy. The eukaryotic expression vector pIRESG2 containing cyclinG2 was transfected into SGC7901 cells by cationic mediated liposome transfection reagent. G418 clones were screened to obtain stable cell clones of cyclinG2, MTT assay was used to determine the change of cell proliferation after transfection. Results ① The positive rate and the expression intensity of CyclinG2 in non-cancerous tissue, differentiated carcinoma and differentiated carcinoma tissue decreased gradually and the difference was statistically significant (P <0.01). ② The proliferation of cloned cells transfected with pIRESG2 decreased in vitro (P <0.01). Conclusions CyclinG2 gene may be a candidate tumor suppressor gene, whose expression is decreased with the increase of malignant degree of gastric cancer. Abnormal high expression of cyclinG2 induced by exogenous gene transfection can significantly inhibit the proliferation of gastric cancer cell line in vitro.