肺鳞癌PD-L1共表达基因及转录调控网络分析

摘要

Objective To construct a programmed cell death ligand 1(PD-L1) co-expression network in lung squamous cell carcinoma,screen potential PD-L1 co-expression biomarkers,and try to find the genes and pathways participating in PD-L1-regulated tumor immune response.Methods The lung squamous cell carcinoma dataset extracted from TCGA was used to screen the co-expression genes of PD-L 1 at the whole-genome transcriptional level by Venny analysis,and the target genes were screened by multiple types of cluster and molecular network analysis to construct a PD-L1 co-expression network.Results A total of 126 genes moderately co-expressed with PD-L1 were retrieved,most of them are plasma membrane targeting genes participating in immune response.Three transcription factors (IRF2/NFKB1/IRF1) were involved in more than 30％ the regulation of the PD-L1 genes transcription.By screening the core molecules of co-expression of PD-L1 gene set and analyzing the connectivity of network node,6 network nodes genes with the highest connectivity were retrieved as follows:IFNG,JAK2,STAT1,CTLA4,CD80 and CCR5.Analysis of the relations of the different expression levels of these genes to the survival situation of patients with lung cancer revealed that CCR5 was a significant prognostic marker.Analysis of the PD-L1 expression and CCR5 gene spectrum data showed the Pearson correlation coefficient is 0.47(P＜0.05);GO-BP cluster analysis showed that the function of CCR5 mainly focused on immune regulation,T cell regulation and signal transduction,in accordance with the PD-L1 function of network regulation.Conclusions The main nodes of PD-L1 co-expressing gene set are immune-related molecules,among which IFNG/CCR5/NFKB1 play the most significant regulatory effects in the gene network.This finding lays a foundation for the research and immunotherapy for lung squamous cell carcinoma.%目的 绘制肺鳞癌中细胞程序性死亡配体1(PD-L1)共表达基因关系网络,筛选潜在的PD-L1协同检测生物标志物,寻找可能参与PD-L1调控肿瘤免疫状态的基因及通路.方法 采用TCGA肺鳞癌数据集,利用cBioPortal数据分析平台进行共表达基因集检索,从全基因转录组水平对PD-L1的共表达基因进行Venny分析,筛选目标基因,进行多种类型的聚类和分子关系网络分析,并建立PD-L1调控网络.结果 共获得PD-L1中等程度表达相关基因126个,主要为质膜定位型基因,功能集中在免疫调节过程,其中IRF2/NFKB 1/IRF1三个转录因子参与了对PD-L1基因集30％以上基因的转录调控.经过PD-L1共表达基因集的核心分子筛选,分析网络节点连接度,得到具有最高连接度的前6个节点基因,依次为IFNG、JAK2、STAT1、CTLA4、CD80和CCR5,对这些基因不同表达水平的肺癌患者的生存情况进行分析,结果显示CCR5是一个有意义的预后指标分子.进一步对PD-L1和CCR5的表达谱数据进行相关性分析,结果显示CCR5与PD-L1表达谱水平的Pearson相关系数为0.47(P＜0.05);GO-BP聚类分析显示,CCR5的功能主要聚集在免疫调控、T细胞调控、细胞信号转导等领域,与PD-L1调控网络的功能相符.结论 PD-L1共表达基因集内的主要节点均为免疫相关分子,其中IFNG、CCR5、NFKB1分子对PD-L1共表达基因网络具有最广泛的调控作用,该发现为肺鳞癌免疫治疗的研究和应用奠定了一定基础.