目的：探讨沉默厚体1（DKK1）基因对胃癌AGS细胞增殖、周期和凋亡的影响及其作用机制。方法：构建DickkopfsiRNA（DKK1-siRNA）稳定转染细胞株，提取稳定转染细胞的RNA及总蛋白，qPCR和WB实验分别检测DKK1 mRNA及蛋白的表达水平。实验分为空白对照（Control）组、阴性对照（shNC）组及沉默DKK1（DKK1-shRNA）组，CCK-8 实验检测各组培养0、24、48、72、96、120、144 h 后AGS细胞的增殖情况，流式细胞术检测细胞周期和细胞凋亡水平。检索HPA数据库，分析DKK1 与胃癌临床病理的关系。结果：成功建立了稳定沉默DKK1 基因的胃癌细胞株AGS，证实DKK1-shRNA组细胞中DKK1 mRNA及蛋白表达水平分别比Control 组和shNC组降低到72%和47%（均P<0.05）。细胞增殖曲线显示，与Control 和shNC组比较，DKK1-shRNA组细胞培养72 h 后其增殖显著降低（P<0.05）。与shNC组比较，DKKl-shRNA组S期细胞从32.06%降低到25.87%，G2/M期细胞由8.49%上升到21.26%，细胞凋亡率从10.34%上升到20.65%，差异均有统计学意义（均P<0.05）。HPA数据库的分析显示，胃癌组织中DKK1 mRNA水平显著高于胃正常组织，DKK1 mRNA的高表达与胃癌患者生存率呈负相关（均P<0.05）。结论：沉默DKK1基因可抑制胃癌AGS细胞的增殖，阻滞细胞于G2/M期并促进细胞凋亡；DKK1在胃癌中发挥促癌作用。

Objective：To study the effect of silencing DKK1 (Dickkopf1) gene on the proliferation, cell cycle and apoptosis of gastric cancer AGS cells and the action mechanism. Methods：The DKK1-shRNA vector was constructed and transfected into AGS cells. The stably transfected cell lines were screened. The total protein and RNA of the transfected cells were extracted and the mRNA and protein expressions of DKK1 were detected by qPCR and WB, respectively. The experiment was divided into blank control group (Control),negative control group (shNC) and DKK1 silence group (DKK1-shRNA). CCK8 assay was used to detect the proliferation of AGS cells of each group cultured for 0, 24, 48, 72, 96, 120 and 144 h, and flow cytometry was used to analyze the cell cycle and apoptosis in each group. The relationship between DKK1 and clinicopathological features of gastric cancer was analyzed after searching HPA database.Results：The gastric cancer AGS cells with stable DKK1 gene knockdown was successfully established, and it was confirmed that the mRNA and proteinexpressions of DKK1 in DKK1-shRNA group decreased by 72% and 47%, respectively, compared to shNC group (all P<0.05). The cell proliferation curve showed that, the cell proliferation in DKKl-shRNA group significantly decreased after 72 hour of culture compared with that in control and shNC groups (P<0.05). The cell number of S phase decreased from 32.06% to 25.87%,while the number of G2/M phase increased from 8.49% to 21.26% compared with shNC group (all P<0.05). The number of apoptotic cells also statistically increased from 10.34% to 20.65% (all P<0.05). The data of HPA database showed that DKK1 mRNA level in gastric cancer tissues was significantly higher than that in normal tissues, and the high expression of DKK1 mRNA was negatively correlat‐ed with the survival rate of gastric cancer patients. Conclusion: Silencing DKK1 gene can inhibit the proliferation of gastric cancer cells, arrest cells in G2/M phase and promote cell apoptosis. DKK1 plays a pro-carcinogenic effect in gastric cancer.

国家自然科学基金资助（No.31560326, No.31760328, No. 31660031）；贵州省科技计划资助项目（No. [2017]5652）；贵阳市科技计划资助项目（No. [2017]5-16, [2017]30-4）