高表达RAB7A通过促进肿瘤侵袭影响胃癌患者的预后

High expression of RAB7A is associated with poor prognosis of gastric cancer by promoting tumor invasion

目的探讨Ras相关蛋白7A(RAB7A)在胃癌组织中的表达对预后的影响及其作用机制。方法基于癌症公共数据库和本院接受胃癌根治术的104例患者,分析RAB7A在胃癌及癌旁组织中表达的差异以及其与患者临床病理学参数和预后的关系;采用生物信息学富集分析预测RAB7A影响胃癌侵袭途径的作用和机制;通过慢病毒转染获得过表达和低表达RAB7A的胃癌细胞系(MGC803),采用免疫印迹、划痕及Transwell实验探究RAB7A对ECM降解的影响以及RAB7A对胃癌细胞迁移、侵袭的作用和机制。结果癌症公共数据库分析显示胃癌组织中RAB7A的表达高于正常对照组,且负面影响患者生存期(P<0.01)。本院患者数据显示,胃癌组织中RAB7A的表达高于癌旁组织(P<0.01),且与外周血胚抗原、糖类抗原19-9水平正相关(P<0.001)。单因素结合Cox多因素分析显示,RAB7A高表达是影响胃癌5年生存率的独立危险因素(HR:2.882;95%CI:1.459~5.693);ROC曲线分析显示,以RAB7A相对表达量2.625为截断值,其预测患者术后5年死亡的敏感性为84.62%,特异性为71.15%。生物信息学富集分析显示,RAB7A参与了胃癌组织ECM降解和PI3K/AKT信号激活;体外实验证实,过表达RAB7A可激活胃癌细胞PI3K/AKT信号(P<0.01),增强基质金属蛋白酶(MMP-2和MMP-9)表达(P<0.01),以及胃癌细胞迁移和侵袭能力(P<0.01)。结论RAB7A在胃癌组织中高表达并影响患者预后,其作用和激活胃癌PI3K/AKT信号并促进ECM降解和肿瘤侵袭有关。

Objective To explore the expression level of Ras-related protein 7A(RAB7A)in gastric cancer and its prognostic implications.Methods Based on data from public databases and a cohort of 104 patients undergoing radical gastrectomy for gastric cancer in our hospital,we analyzed RAB7A expression level in gastric cancer and adjacent tissues and its association with clinicopathological parameters and prognosis of the patients.Bioinformatic analysis was performed to predict the pathways of RAB7A to affect gastric cancer invasion.In gastric cancer MGC803 cells with lentivirus-mediated interference or overexpression of RAB7A,the changes in extracellular matrix(ECM)degradation and cell migration and invasion were analyzed using immunoblotting,wound healing assay and Transwell experiments.Results The data from public cancer databases and clinical samples showed a significantly higher expression of RAB7A in gastric cancer tissues than in normal or adjacent tissues(P<0.01)with a close correlation with a poorer patient survival(P<0.01)and a positive correlation with serum carcinoembryonic antigen and carbohydrate antigen 19-9 levels(P<0.001).Univariate and multivariate Cox regression analyses suggested that a high RAB7A expression was an independent risk factor affecting the 5-year survival rate of gastric cancer patients(HR:2.882;95%CI:1.459-5.693).ROC curve analysis showed that at the cut-off value of 2.625,RAB7A expression level had a sensitivity of 84.62%and a specificity of 71.15%for predicting postoperative 5-year mortality of the patients.Bioinformatic analysis suggested that RAB7A was involved in ECM degradation and activation of PI3K/AKT signaling in gastric cancer.MGC803 cells with RAB7A overexpression showed activation of the PI3K/AKT signaling pathway(P<0.01)with enhanced expressions of MMP-2 and MMP-9(P<0.01)and cell migration and invasion capacities(P<0.01).Conclusion RAB7A is highly expressed in gastric cancer tissues and affects the patients'prognosis possibly by activating the PI3K/AKT signaling pathway and enhancing ECM degradation to promote tumor invasion.