肺腺癌预后关键基因的筛选、验证及其调控通路分析

Screening,validation and regulatory pathway analysis of key prognostic genes in lung adenocarcinoma

目的筛选肺腺癌预后关键基因并进行验证,分析其调控通路。方法从TCGA和GEO数据库获取肺腺癌转录组数据,筛选共同差异表达基因。将LASSO引入到COX回归模型中,进一步筛选预后关键基因。计算TCGA数据库获得的500例肺腺癌患者的预后关键基因相关风险评分,以风险评分中位数作为临界值将患者分为高风险组和低风险组,比较两组5年生存率。采用GEPIA数据库分析癌组织预后关键基因表达,Kaplan Meier-plotter数据库分析预后关键基因表达与肺腺癌患者预后的关系。采用基因集变异分析(GSVA)预测肺腺癌预后关键基因的调控通路。结果在TCGA、GEO数据库共得到166个共同差异表达基因,回归分析筛选出DCN、RRAS、ECT2和PCP4是肺腺癌预后关键基因。高、低风险组5年生存率分别为29.3%、48.4%,两组比较P<0.01。肺腺癌组织中DCN、RRAS mRNA表达均低于正常肺组织,PCP4、ECT2 mRNA表达均高于正常肺组织(P均<0.05)。RRAS、PCP4、ECT2高表达者5年生存率明显低于低表达者,DCN高表达者5年生存率明显高于低表达患者(P均<0.01)。GSVA结果显示,DCN、RRAS、ECT2和PCP4可能通过调节细胞周期、DNA损伤修复等途径影响肺腺癌患者的预后。结论DCN、RRAS、ECT2和PCP4是肺腺癌患者预后相关的关键基因,癌组织RRAS、PCP4、ECT2表达升高及DCN表达降低均提示预后不良,其调控通路可能与调节细胞周期及DNA损伤修复等有关。

Objective To screen and validate the key genes related to the prognosis of lung adenocarcinoma,and to explore its regulatory pathway.Methods Transcriptome data of lung adenocarcinoma were downloaded from GEO and TCGA database to screen out the common differentially expressed genes.Lasso was introduced into the Cox model for further screening of key genes associated with prognosis.We calculated the risk scores of 500 patients with lung adenocarcinoma obtained from TCGA database,and then the patients were divided into the high-risk group and the low-risk group;with the median risk score as the critical value,we compared the 5-year survival rates of the two groups.GEPIA and HPA databases were used to analyze the expression of key prognostic genes and their proteins in cancer tissues.Kaplan-Plotter database was used to analyze the relationship between key prognostic genes and the prognosis of patients with lung adenocarcinoma.TIMER databases were utilized to analyze the correlation between the abundance of 6 immune infiltrating cells and the expression of key prognostic genes in lung adenocarcinoma.Gene Set variation Analysis(GSVA)method was used to predict the regulatory pathways of key prognostic genes in lung adenocarcinoma.Results Totally,166 common differentially expressed genes were identified from TCGA and GEO databases.Regression analysis screened out DCN,RRAS,ECT2 and PCP4 as key genes related to the prognosis of lung adenocarcinoma.The 5-year survival rates of the high-risk and low risk groups were 29.3%and 48.4%,respectively(both P<0.01).Compared with the normal tissues,the expression levels of DCN,RRAS mRNA and protein in the lung adenocarcinoma tissues were down-regulated,while the expression levels of PCP4 and ECT2 mRNA and protein were up-regulated in the lung adenocarcinoma tissue(all P<0.05).The 5-year survival rate of patients with high RRAS,PCP4 and ECT2 expression was significantly lower than that of patients with low expression,and the 5-year survival rate of patients with high DCN expression was significantly higher than that of patients with low expression(all P<0.01).GSVA results revealed that DCN,RRAS,ECT2 and PCP4 might affect the prognosis of lung adenocarcinoma by regulating cell cycle,DNA damage repair and other pathways.Conclusions DCN,RRAS,ECT2 and PCP4 are key genes related to prognosis in patients with lung adenocarcinoma.The high expression of RRAS,PCP4 and ECT2 and the low expression of DCN in the cancer tissues all indicate poor prognosis,and the mechanism may be related to activation of immune cells,regulation of cell cycle,DNA damage repair and other pathways.