E2F转录因子5在食管腺癌中高表达

High Expression of E2F Transcription Factor 5 in Esophageal Adenocarcinoma

摘要: 背景：E2F转录因子5 (E2F Transcription Factor 5, E2F5)在多种肿瘤中表达异常升高且与肿瘤进展密切相关，然而其在食管腺癌(Esophageal Adenocarcinoma, EAC)中mRNA表达水平的变化及其对肿瘤细胞增殖、免疫微环境的影响尚未被系统研究。目的：探究E2F5在EAC中mRNA水平表达特征及敲除E2F5对EAC细胞增殖的影响。方法：在mRNA层面，通过整合来自基因表达综合数据库(Gene Expression Omnibus, GEO)和癌症基因组图谱(The Cancer Genome Atlas, TCGA)等公共数据库中EAC和非EAC样本的芯片及RNA测序数据，采用标准化均数差(Standard Mean Difference, SMD)进行分析。在细胞水平，基于依赖性图谱(Dependency Map, DEPMap)数据库中CRISPR-Cas9敲除筛选数据，评估E2F5对EAC细胞增殖的影响。通过单样本基因集富集分析(Single Sample Gene Set Enrichment Analysis, ssGSEA)评估E2F5表达与免疫细胞浸润的相关性，并对E2F5高低表达共调控基因进行KEGG和GO富集分析。结果：共纳入EAC样本322例，非EAC对照组样本551例。E2F5 mRNA在EAC中显著上调，SMD为1.02 (95% CI [0.24; 1.79])。分析CRISPR敲除筛选结果相关数据证实E2F5是EAC细胞增殖的关键调控因子，其中SH10TC细胞系对E2F5依赖性较强(SCORE < 0)。免疫浸润分析表明，Th2细胞和辅助T细胞与E2F5表达呈显著正相关(R > 0.2, P < 0.05)，而大多数其他免疫细胞浸润与E2F5高表达呈负相关。功能富集分析显示，E2F5在EAC中主要参与细胞周期和蛋白质加工等过程；而MAPK、Ras、Hippo、mTOR等信号通路及轴突导向与表皮发育等功能被显著富集。结论：本研究揭示了E2F5作为EAC潜在生物标志物和治疗靶点的价值，为深入研究EAC的发病机制提供重要的理论依据。

Abstract: Background: E2F Transcription Factor 5 (E2F5) exhibits abnormally elevated expression in multiple tumors and is closely associated with tumor progression. However, the changes in mRNA expression in Esophageal Adenocarcinoma (EAC) and its effects on tumor cell proliferation and immune microenvironment have not been systematically studied. Objective: To investigate the mRNA level expression characteristics of E2F5 in EAC and the effect of knockdown of E2F5 on EAC cell proliferation. Methods: At the mRNA level, integrated microarray and RNA sequencing data from EAC and non-EAC samples were obtained from public databases, including Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA). And the Standardized Mean Difference (SMD) was employed for analysis. At the cellular level, the effect of E2F5 on the proliferation of EAC cells was assessed based on CRISPR-Cas9 knockdown screening data from the Dependency Map (DEPMap) database. The correlation between E2F5 expression and immune cell infiltration was assessed using Single Sample Gene Set Enrichment Analysis (ssGSEA). KEGG and GO enrichment analyses were performed on co-regulated genes by high and low E2F5 expression. Results: A total of 322 EAC samples and 551 non-EAC control samples were included. E2F5 mRNA was significantly upregulated in EAC, with an SMD of 1.02 (95% CI [0.24; 1.79]). Analysis of CRISPR knockout screening data confirmed that E2F5 is a key regulator of EAC cell proliferation, with the SH10TC cell line showing strong dependency on E2F5 (SCORE < 0). Immune infiltration analysis revealed that Th2 cells and helper T cells showed a significant positive correlation with E2F5 expression (R > 0.2, P < 0.05), whereas most other immune cell infiltrations were negatively correlated with high E2F5 expression. Functional enrichment analysis showed that E2F5 was primarily involved in cell cycle and protein processing in EAC, and was significantly enriched in signaling pathways such as MAPK, Ras, Hippo, and mTOR, as well as functions like axon guidance and epidermal development. Conclusion: This study reveals the value of E2F5 as a potential biomarker and therapeutic target of EAC, providing an important theoretical basis for in-depth research of the pathogenesis of EAC.