BZW1高表达促进胃癌细胞的侵袭和转移:基于调控Wnt//β-catenin通路和促进上皮间质转化

Overexpression of BZW1 promotes invasion and metastasis of gastric cancer cells by regulating Wnt/β-catenin signaling and promoting epithelial-mesenchymal transition

目的明确碱性亮氨酸拉链蛋白1(BZW1)在胃癌中的表达情况,并探讨其对胃癌患者预后的影响及其可能的作用机制。方法分别采用TIMER、UALCAN和Kaplan-Meier Plotter数据库分析BZW1在胃癌组织中的表达情况,与肿瘤分级、分期之间的相关性及对患者预后的影响。纳入2014年1月~2016年12月在我院行胃癌根治术的102例患者,分析BZW1在胃癌组织中的表达水平、对胃癌疾病进展和患者术后5年生存率的影响。体外采用慢病毒转染的方式构建上调和下调BZW1表达的胃癌细胞系(MGC803),分析BZW1对MGC803细胞迁移、侵袭及上皮-间质转化(EMT)的作用。采用KEGG富集分析预测BZW1在胃癌中的可能作用机制,并进一步采用Western blot实验进行体外验证。结果生物信息学分析结果显示,BZW1在胃癌和癌旁组织中的表达量差异有统计学意义(P<0.01),免疫组化和RT-qPCR结果显示,BZW1在胃癌组织中的蛋白和mRNA表达水平分别是癌旁组织的3.30倍和6.54倍(P<0.01);胃癌组织中BZW1的表达水平与外周血CEA和CA199水平呈正相关(P<0.01);单因素结合Cox多元回归模型分析证实BZW1高表达(P<0.05,HR=2.070,95%CI:1.021~4.196)是影响胃癌患者根治术后5年生存率的独立危险因素;以BZW1相对表达量3.61为截点值,预判术后5年死亡的敏感性为75.56%,特异性为71.93%(P<0.01)。Transwell实验显示,上调BZW1可促进MGC803细胞的迁移和侵袭(P<0.05),下调则相反(P<0.05)。Western blot实验发现,上调BZW1可促进MGC803细胞N-cadherin与Vimentin的表达(P<0.05),并抑制E-cadherin的表达(P<0.05),下调则反之(P<0.05)。富集分析显示,BZW1生物功能可能与Wnt//β-catenin信号相关。Western blot实验进一步证实,上调BZW1可促进Wnt3a、β-Catenin及C-myc的表达(P<0.05),而下调则相反(P<0.05);使用Wnt通路抑制剂XAV-939可显著削弱上调BZW1对MGC803细胞中EMT关键分子的蛋白N-cadherin、Vimentin及E-cadherin的调控作用(P<0.05)。结论BZW1在胃癌组织中高表达并影响患者预后,可能与调控Wnt/β-catenin信号促进胃癌细胞EMT进程相关。

Objective To investigate the expression level of basic leucine zipper and W2 domain-containing protein 1(BZW1)in gastric cancer,its impact on patient prognosis and the underlying mechanisms.Methods TIMER,UALCAN and Kaplan-Meier Plotter databases were used for analyzing BZW1 expression level gastric cancer tissues and its correlation with tumor grade and stage and the patients'prognosis.We further analyzed BZW1 expressions,disease progression,and postoperative 5-year survival in 102 patients undergoing radical surgery for gastric cancer at our hospital between January,2014 and December,2016.Gastric cancer MGC803 cells were examined for changes in migration,invasion,and epithelial-mesenchymal transition(EMT)following lentivirus-mediated BZW1 overexpression or knockdown.Results The protein and mRNA expressions of BZW1 in gastric cancer tissues were 3.30 and 6.54 times of those in adjacent tissues,respectively(P<0.01).BZW1 expression in gastric cancer tissues were positively correlated with peripheral blood CEA and CA199 levels(P<0.01).A high BZW1 expression was an independent risk factor for 5-year survival of gastric cancer patients after radical surgery(P<0.05,HR=2.070,95%CI:1.021-4.196).At the cut-off value of 3.61,BZW1 expression had a sensitivity of 75.56%and a specificity of 71.93%for predicting postoperative 5-year mortality(P<0.01).In MGC803 cells,BZW1 overexpression obviously promoted cell migration and invasion(P<0.05),enhanced cellular expressions of N-cadherin and vimentin(P<0.05)and inhibited the expression of Ecadherin(P<0.05).Enrichment analysis suggested the involvement of BZW1 in the Wnt/β-catenin signaling pathway.Western blotting confirmed that BZW1 overexpression promoted while BZW1 knockdown inhibited the expressions of Wnt3a,β-catenin and C-myc in MGC803 cells(P<0.05).Conclusion BZW1 is highly expressed in gastric cancer tissues to affect the patient prognosis possibly by activation the Wnt/β-catenin signaling pathway to promote EMT of gastric cancer cells.