长链非编码RNA-TUG1在胃癌发生和发展中的作用及其机制

Role and mechanism of long noncoding RNA-TUG 1 in the development and progression of gastric cancer

目的探讨长链非编码RNA(lncRNA)TUG1在胃癌发生和发展中的作用及其机制。方法收集2018年10月—2020年9月于上海健康医学院附属嘉定区中心医院普外科行胃癌根治术的60例胃癌患者的肿瘤组织和癌旁组织标本。选取其中3例存在淋巴结转移的患者组织样本进行lncRNA芯片检测,筛查胃癌和癌旁组织样本中的差异表达lncRNA。采用qRT-PCR技术检测TUG1基因在胃癌组织和细胞中的表达水平,分析其表达水平与临床及病理因素之间的关系。采用慢病毒Lenti-TUG1、Lenti-TUG1-shRNA转染胃癌细胞NCI-N87和MGC-803。根据慢病毒转染分为Lenti-TUG1处理组与Lenti-TUG1-shRNA处理组,设计不加慢病毒的细胞为对照组。采用细胞增殖实验和动物模型实验检测TUG1基因在体外和体内对NCI-N87和MGC-803生长的影响;采用细胞迁移和侵袭实验检测TUG1基因对NCI-N87和MGC-803细胞迁移和侵袭的影响;采用细胞凋亡实验检测TUG1基因对NCI-N87和MGC-803细胞凋亡的影响;采用蛋白质印迹法检测TUG1基因对凋亡及上皮间质转化(EMT)相关蛋白质表达的影响。结果lncRNA芯片检测结果显示,与癌旁组织比较,胃癌组织中有11种lncRNAs表达上调,有7种lncRNAs表达下调。根据患者胃癌组织中TUG1的中位相对表达量,将胃癌患者分为高表达组(30例)和低表达组(30例)。TUG1高表达组肿瘤体积≥5 cm^(3)、有淋巴结转移、有远处转移、TNM分期为Ⅲ期的患者构成均显著高于TUG1低表达组(P值均<0.05)。细胞增殖实验结果显示,与对照组比较,Lenti-TUG1处理组NCI-N87细胞和MGC-803细胞的光密度(A)值均显著增高,Lenti-TUG1-shRNA处理组NCI-N87细胞和MGC-803细胞的A值均显著降低(P值均<0.01)。细胞迁移和侵袭实验结果显示,与对照组相比,Lenti-TUG1处理组NCI-N87细胞与MGC-803细胞的迁移数量和侵袭数量均显著增多,Lenti-TUG1-shRNA处理组NCI-N87细胞与MGC-803细胞的迁移数量和侵袭数量均显著减少(P值均<0.01)。细胞凋亡实验结果显示,与对照组相比,Lenti-TUG1处理组NCI-N87细胞和MGC-803细胞的凋亡比例均显著降低,Lenti-TUG1-shRNA处理组NCI-N87细胞和MGC-803细胞的凋亡比例均显著增高(P值均<0.01)。小动物活体成像仪检测结果显示,与对照组相比,Lenti-TUG1处理组的NCI-N87细胞和MGC-803细胞的相对荧光强度均显著增高(P值均<0.01),Lenti-TUG1-shRNA处理组NCI-N87细胞和MGC-803细胞相对荧光强度均显著降低(P值均<0.01)。蛋白质印迹法检测结果显示,与对照组相比,Lenti-TUG1处理组NCI-N87细胞和MGC-803细胞中Bax、caspase-3和E-cadherin的蛋白质相对表达量均显著降低,RAB2A、MMP-14和Bcl-2的蛋白质相对表达量均显著增高;Lenti-TUG1-shRNA处理组NCI-N87细胞和MGC-803细胞中Bax、caspase-3和E-cadherin蛋白质相对表达量均显著增高,RAB2A、MMP-14和Bcl-2蛋白质相对表达量均显著降低(P值均<0.01)。在229例胃癌组织中,TUG1与RAB2A相对表达量呈正相关(r=0.180,P=0.006);miR-186与RAB2A相对表达量呈负相关(r=-0.147,P=0.026)。结论TUG1可能通过调控凋亡、EMT相关信号通路参与胃癌的发生、发展,针对TUG1的靶向治疗设计可能为胃癌治疗提供新的思路。

Objective To evaluate the role and mechanism of TUG 1,a long noncoding RNA(lncRNA)in the development and progression of gastric cancer.Methods Tumor tissue and paracancerous tissue specimens of 60 gastric cancer patients who underwent radical gastrectomy from October 2018 to September 2020 in Jiading District Central Hospital affiliated to Shanghai University of Medicine&Health Sciences were collected.Tissue samples from three of these patients with lymph node metastasis were selected for lncRNA microarray detection to screen for differentially expressed lncRNAs in gastric cancer and paracancerous tissue samples.The expression level of TUG 1 in gastric cancer tissues and cells were detected by using real-time fluorescence quantitative polymerase chain reaction.The relationship between the expression level and clinicopathological factors was investigated.The lentiviruses Lenti-TUG 1 and Lenti-TUG 1-shRNA were used to transfect gastric cancer cells NCI-N87 and MGC-803.Gastric cancer cells were divided into the Lenti-TUG 1-treated group and the Lenti-TUG 1-shRNA-treated group according to lentiviruses transfection.Cells designed without lentivirus were the control group.CCK-8 and animal model experiments were carried out to determine the effects of TUG 1 gene on the proliferation of NCI-N87 and MGC-803 in vitro and in vivo.Transwell assay was performed to determine the effects of TUG 1 gene on the migration and invasion of NCI-N87 and MGC-803.Annexin V/PI staining assay was performed to determine the effects of TUG 1 gene on the apoptosis of NCI-N87 and MGC-803.Western blotting was performed to determine the effects of TUG 1 gene on the expression of apoptosis-and epithelial-mesenchymal transition(EMT)-related proteins.Results The results of lncRNA microarray showed that there were 11 lncRNAs with up-regulated expression and 7 lncRNAs with down-regulated expression in gastric cancer tissues compared with paracancerous tissues.Based on the median relative expression of TUG 1 in the gastric cancer tissues,the patients were divided into a high expression group(n=30)and a low expression group(n=30).The proportions of patients with tumor volume≥5 cm 3,lymph node metastasis,distant metastasis,and TNM stageⅢin the high expression group were significantly higher than those in the low expression group(all P<0.05).The results of cell proliferation assay showed that the optical density of NCI-N87 and MGC-803 cells in the Lenti-TUG 1-treated group was significantly higher than that in the control group,and the optical density of NCI-N87 and MGC-803 cells in the Lenti-TUG 1-shRNA-treated group was significantly lower than that in the control group(all P<0.01).The results of cell migration and invasion assays showed that compared with the control group,the number of migrating and invading NCI-N87 and MGC-803 cells in the Lenti-TUG 1-treated group were significantly increased,and the number of migrating and invading NCI-N87 and MGC-803 cells in the Lenti-TUG 1-shRNA-treated group were significantly decreased(all P<0.01).The results of apoptosis assay showed that compared with the control group,the apoptosis rates of NCI-N87 and MGC-803 cells in the Lenti-TUG 1-treated group were significantly reduced,and the apoptosis rates of NCI-N87 and MGC-803 cells in the Lenti-TUG 1-shRNA-treated group were significantly elevated(all P<0.01).The results of small animal in vivo imaging experiments showed that compared with the control group,the relative fluorescence intensity of NCI-N87 and MGC-803 cells in the Lenti-TUG 1-treated group was significantly increased,and the relative fluorescence intensity of NCI-N87 and MGC-803 cells in the Lenti-TUG 1-shRNA-treated group was significantly reduced(all P<0.01).The results of Western blotting showed that the relative protein expression of Bax,caspase-3 and E-cadherin was significantly decreased,and the relative protein expression of RAB2A,MMP-14 and Bcl-2 was significantly increased in NCI-N87 and MGC-803 cells in the Lenti-TUG 1-treated group as compared with those in the control group;the opposite results were obtained in the Lenti-TUG 1-shRNA-treated group(all P<0.01).In 229 gastric cancer tissues,TUG 1 was positively correlated with the expression of RAB2A gene(r=0.180,P=0.006),and miR-186 was negatively correlated with the expression of RAB2A gene(r=-0.147,P=0.026).Conclusion TUG 1 gene may regulate the development and progression of gastric cancer through apoptosis-and EMT-related signaling pathway,which may be a potential target for the treatment of gastric cancer.