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@#[摘 要] 目的：探讨幽门螺杆菌（Helicobacter pylori, Hp）感染对胃癌细胞共济失调毛细血管扩张突变（ataxia-telangiectasia mutated，ATM）基因表达的影响及其临床意义。方法：从TCGA数据库中获取胃癌相关RNAseq数据，比较ATM基因的表达差异，分析ATM表达与患者临床病理参数的相关性及预后价值，用Kaplan-Meier法进行生存分析，LinkedOmics数据库分析ATM相关基因，用R语言进行GO、KEGG富集分析。选用2019年3月至2019年12月贵州医科大学附属医院12例手术切除的胃癌及癌旁组织标本，以及胃癌细胞系AGS和BGC823，用感染复数40∶1的Hp GZ7菌感染细胞，用免疫组织化学染色法检测胃癌组织中ATM蛋白的表达，qPCR法检测胃癌组织和细胞中ATM mRNA的表达。结果：TCGA数据显示胃癌和Hp感染胃癌组织中ATM miRNA表达水平均显著高于癌旁组织（均P<0.01）；胃癌组织中ATM miRNA表达与患者的T分期、AJCC分期等病理参数呈正相关（均P<0.05），ATM高表达时生存率显著降低（P<0.05）。实验检测显示，胃癌组织标本中ATM蛋白的表达水平明显高于癌旁组织（P<0.01）；Hp感染胃癌细胞中ATM miRNA表达水平显著高于未感染胃癌细胞（P<0.01）。胃癌中ATM基因与NPAT等12 461个基因呈正相关（P<0.05），与MIF等7 764个基因呈负相关（P<0.05）。GO、KEGG富集分析显示，ATM富集到DNA修复复合体、癌症中的转录失调等信号通路。结论：ATM基因在胃癌组织中高表达，患者生存率随表达水平的增高而降低，其与患者的T分期、AJCC分期等病理参数相关，且Hp感染引起ATM表达水平升高可能是Hp引起胃癌的原因之一。
RESUMO
@# 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 RNAof the transfected cells were extracted and the mRNAand 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 ofAGS 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-shRNAgroup 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 HPAdatabase showed that DKK1 mRNAlevel in gastric cancer tissues was significantly higher than that in normal tissues, and the high expression of DKK1 mRNAwas 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.