基于生物信息学分析IPO7在肝癌中的表达及意义

Expression and significance of IPO7 in hepatocellular carcinoma based on bioinformatics analysis

目的基于生物信息学分析探讨输入蛋白7(IPO7)在肝细胞癌(肝癌)中的表达及临床意义。方法利用TIMER 2.0、UALCAN及CPTAC数据库分析IPO7在肝癌中的表达情况,并从GEO数据库下载多个基因芯片进一步验证。基于GEPIA2、UALCAN数据库分析IPO7表达与肝癌患者临床病理特征的相关性,并利用TCGA肝癌数据进行二元Logistic回归,进一步分析并验证IPO7表达与肝癌患者临床病理特征的相关性。基于GEPIA2、Kaplan-Meier Plotter数据库分析IPO7表达对肝癌患者预后的影响,通过Cox回归模型进一步评估IPO7的预后价值,并进一步构建列线图评估肝癌的预后。基于LinkedOmics数据库,分析IPO7在肝癌中的共表达基因,进行GO功能及KEGG通路富集分析预测其生物学功能。通过STRING数据库进一步构建蛋白质-蛋白质相互作用(PPI)网络。基于TIMER 2.0数据库,分析IPO7表达与肝癌组织免疫浸润水平的关系。两组IPO7表达比较采用t检验或秩和检验,临床分期与IPO7表达关系分析采用单因素方差分析,生存分析采用Kaplan-Meier法及Log-rank检验,采用Cox比例风险回归模型分析IPO7对预后的预测价值。结果UALCAN数据库分析显示,肝癌组织中IPO7 mRNA表达水平中位数为16.9(10.7,23.7),明显高于正常肝组织的11.9(10.3,14.1)(P<0.05)。GEO数据下载多个基因芯片进一步验证,肝癌组织IPO7 mRNA相对表达量明显高于正常肝组织。CPTAC数据库进一步验证,肝癌中IPO7蛋白表达量为0(-0.778,0.654),亦明显高于正常肝组织的-1.582(-2.367,-0.559)(P<0.05)。GEPIA2数据库显示,随着肝癌分期增高,IPO7表达量逐渐升高(F=4.83,P<0.05)。UALCAN数据库显示IPO7 mRNA表达与肝癌患者美国癌症联合委员会(AJCC)临床分期、组织学分级及TP53突变有关(P<0.05)。GEPIA2数据库分析显示,IPO7高表达组总体生存期(OS)及无病生存期(DFS)更短(HR=1.700,1.400;P<0.05);多因素Cox分析显示,IPO7基因表达是肝癌患者预后不良的独立危险因素(HR=1.675,P<0.05)。KEGG通路富集分析和STRING蛋白相互作用网络分析显示,IPO7蛋白主要参与蛋白质核输入、细胞周期调控、转录调节、有丝分裂纺锤体调节和有丝分裂过程的协调、rRNA加工等活动。TIMER 2.0数据库分析显示,IPO7的表达与CD8^(+)T细胞、CD4^(+)T细胞、B细胞、巨噬细胞、中性粒细胞、树突状细胞浸润水平呈正相关(r=0.191,0.364,0.270,0.450,0.485,0.310;P<0.05)。结论IPO7可作为肝癌预后不良标志物和潜在治疗靶点,其可能通过调节核质转运影响细胞周期及免疫细胞浸润相关通路调控肝癌的发生与发展。

Objective To investigate the expression and clinical significance of importin 7(IPO7)in hepatocellular carcinoma(HCC)based on bioinformatics analysis.Methods The expression level of IPO7 in HCC was analyzed by TIMER 2.0,UALCAN and CPTAC databases,and multiple gene chips were downloaded from GEO database for further verification.The correlation between IPO7 expression and clinicopathological characteristics of HCC patients was analyzed based on GEPIA2 and UALCAN databases.Binary Logistic regression was conducted using TCGA HCC data to further analyze and validate the correlation between IPO7 expression and clinicopathological characteristics of HCC patients.Based on GEPIA2 and Kaplan-Meier Plotter databases,the effect of IPO7 expression on clinical prognosis of HCC patients was analyzed.Prognostic value of IPO7 was further evaluated by Cox regression model and nomogram was constructed to evaluate clinical prognosis of HCC.Based on LinkedOmics database,the co-expression genes of IPO7 in HCC were analyzed.GO function and KEGG pathway enrichment analyses were performed to predict biological function.Protein-protein interaction(PPI)network was further constructed through STRING database.Based on TIMER 2.0 database,the relationship between IPO7 expression and immune infiltration level of HCC was analyzed.The expression level of IPO7 between two groups was compared by t test orrank-sum test.The relationship between clinical staging and IPO7 expression was assessed by One Way ANOVA.Survival analysis was conducted by Kaplan-Meier method and Log-rank test.The prognostic value of IPO7 was determined by Cox proportional hazard regression model.Results UALCAN database analysis showed that the median expression level of IPO7 mRNA in HCC tissues was 16.9(10.7,23.7),significantly higher than 11.9(10.3,14.1)in normal liver tissues(P<0.05).Multiple gene chips downloaded from GEO database further validated that relative expression level of IPO7 mRNA in HCC tissues was significantly higher compared with that in normal liver tissues.CPTAC database further verified that the expression of IPO7 protein was 0(-0.778,0.654)in HCC,significantly higher than-1.582(-2.367,-0.559)in normal liver tissues(P<0.05).GEPIA2 database showed that the expression level of IPO7 was gradually up-regulated with the increase of stages of HCC(F=4.83,P<0.05).UALCAN database indicated that the expression of IPO7 mRNA was correlated with AJCC clinical staging,histological grading and TP53 mutation(P<0.05).GEPIA2 database analysis revealed that the overall survival(OS)and disease-free survival(DFS)were shorter in the high IPO7 expression group(HR=1.700,1.400;P<0.05).Multivariate Cox analysis showed that the expression of IPO7 mRNA was an independent risk factor for poor prognosis in HCC patients(HR=1.675,P<0.05).KEGG pathway enrichment and protein-protein interaction(PPI)network analyses with STRING database indicated that IPO7 protein mainly participated in the transfer of protein to the nucleus,cell cycle regulation,transcription regulation,mitotic spindle regulation,coordination of mitosis and rRNA processing,etc.TIMER 2.0 database analysis showed that the expression level of IPO7 was positively correlated with the infiltration levels of CD8^(+)T cells,CD4^(+)T cells,B cells,macrophages,neutrophils and dendritic cells(r=0.191,0.364,0.270,0.450,0.485,0.310;P<0.05).Conclusions IPO7 can be used as a biomarker for poor prognosis and potential therapeutic target for HCC,which regulates the incidence and development of HCC probably by regulating nucleo-cytoplasmic transport,affecting cell cycle and immune cell infiltration-related signaling pathways.