肺腺癌组织中乙醛脱氢酶2降低的机制及其与患者预后的关系

Mechanism of Decreased Aldehyde Dehydrogenase 2 in Lung Adenocarcinoma Tissue and Its Relationship with Patient Prognosis

目的探讨肺腺癌组织中乙醛脱氢酶2(ALDH2)降低的机制及其与患者预后的关系。方法(1)数据库分析。采用UALCAN数据库分析肺腺癌组织及癌旁组织中ALDH2 mRNA表达每百万转录本和蛋白表达Z分数;采用甲基化数据可视化工具(SMART)分析泛癌模块、4种探针肺腺癌组织中和癌旁组织中ALDH2 DNA甲基化水平;采用基因表达谱互动分析(GEPIA)数据库分析肺腺癌组织中ALDH2 mRNA表达水平与细胞周期调控蛋白表达水平的相关性;采用TIMER 2.0数据库中数据分析肺腺癌组织中ALDH2 mRNA表达水平与6种免疫细胞浸润丰度的相关性。(2)临床试验。回顾性选取2019年1月—2023年1月南通大学杏林学院附属医院收治的行手术治疗的肺腺癌患者55例为研究对象,收集患者的年龄、性别、吸烟史、肿瘤大小、肿瘤分期、手术类型、病理类型,采用免疫组织化学法检测肺腺癌组织及癌旁组织中ALDH2表达水平。对所有患者进行随访,随访截止时间为2024年1月,主要结局事件为死亡。采用Spearman秩相关分析探讨肺腺癌组织中ALDH2 mRNA表达水平与细胞周期调控蛋白表达水平、免疫细胞浸润丰度的相关性;采用单因素、多因素Cox比例风险回归分析探讨肺腺癌患者预后的影响因素;采用K-M法绘制生存曲线,生存率比较采用Log-rank检验。结果(1)数据库分析结果。UALCAN数据库分析结果显示,肺腺癌组织中ALDH2 mRNA表达每百万转录本和蛋白表达Z分数低于癌旁组织(P<0.05)。SMART分析结果显示,泛癌模块肺腺癌组织中ALDH2 DNA甲基化水平较癌旁组织升高(P<0.05);4种探针(cg07106761、cg20884605、cg05212570、cg19848940)肺腺癌组织中ALDH2 DNA甲基化水平较癌旁组织升高(P<0.05)。Spearman秩相关分析结果显示,肺腺癌组织中ALDH2 mRNA表达水平与CDCA2、DEPDC1、ESPL1、EXO1、FAM83D、FANCI、FOXM1、HJURP表达水平呈负相关(P<0.05);肺腺癌组织中ALDH2 mRNA表达水平与B淋巴细胞、CD_(8)^(+)T淋巴细胞、CD_(4)^(+)T淋巴细胞、树突细胞浸润丰度呈正相关,与巨噬细胞、中性粒细胞浸润丰度呈负相关(P<0.05)。(2)临床试验结果。免疫组织化学法分析结果显示,肺腺癌组织中ALDH2表达水平低于癌旁组织(P<0.05)。55例肺腺癌患者生存30例,死亡25例。单因素Cox比例风险回归分析结果显示,年龄、肿瘤大小、肿瘤分期、肺腺癌组织中ALDH2表达水平可能是肺腺癌患者预后的影响因素(P<0.05);多因素Cox比例风险回归分析结果显示,肿瘤分期、肺腺癌组织中ALDH2表达水平是肺腺癌患者预后的独立影响因素(P<0.05)。根据肺腺癌组织中ALDH2表达水平中位数(6.76)将患者分为低表达组28例、高表达组27例。生存曲线分析结果显示,低表达组生存率低于高表达组(P<0.05)。结论肺腺癌组织中ALDH2表达水平降低可能与ALDH2 DNA甲基化水平升高、细胞周期信号的调控和肿瘤微环境的重塑有关。肺腺癌组织中ALDH2表达水平是肺腺癌患者预后的独立影响因素,且ALDH2低表达者生存率更低。

Objective To investigate the mechanism of decreased aldehyde dehydrogenase 2(ALDH2)in lung adenocarcinoma tissue and its relationship with patient prognosis.Methods(1)Database analysis.UALCAN database was used to analyze the ALDH2 mRNA expression per million transcripts and protein expression Z-score in lung adenocarcinoma tissues and paracancerous tissues;the Shiny Methylation Analysis Resource Tool(SMART)was used to analyze the ALDH2 DNA methylation levels in pan-cancer module,four probes of lung adenocarcinoma tissues,and paracancerous tissues;the Gene Expression Profiling Interactive Analysis(GEPIA)database was used to analyse the correlation between the ALDH2 mRNA expression level and cell-cycle-regulated proteins expression level in lung adenocarcinoma tissues;and the data in TIMER 2.0 database were used to analyze the correlation between ALDH2 mRNA expression level and the abundance of six immune cell infiltrations in lung adenocarcinoma tissues.(2)Clinical trial.A total of 55 patients with lung adenocarcinoma undergoing surgical treatment admitted to Affiliated Hospital of Nantong University Xinglin College from January 2019 to January 2023 were retrospectively selected as the study objects,and the age,gender,smoking history,tumour size,tumour stage,surgery type,and pathology type of patients were collected,and immunohistochemistry was used to detect ALDH2 expression level in the tissues of lung adenocarcinoma and the paracancerous tissues.All patients were followed up,and the follow-up cut-off was January 2024,and the primary outcome event was death.Spearman rank correlation analysis was used to explore the correlation between the ALDH2 mRNA expression level and the abundance of cell-cycle-regulated proteins expression level and immune cell infiltration in lung adenocarcinoma tissues.Univariate and multivariate Cox proportional risk regression analysis were used to explore the influncing factors of the prognosis in patients with lung adenocarcinoma;the K-M method was used to draw survival curves,and survival rates were compared using the Log-rank test.Results(1)Database analysis results.The results of UALCAN database showed that ALDH2 mRNA expression per million transcripts and protein expression Z-score in lung adenocarcinoma tissues were lower than those in paracancerous tissues(P<0.05).SMART results showed that the pan-cancer module of lung adenocarcinoma tissues showed a higher ALDH2 DNA methylation level than paracancerous tissues(P<0.05);ALDH2 DNA methylation level was elevated in lung adenocarcinoma tissues of the four probes(cg07106761,cg20884605,cg05212570,cg19848940)compared with paracancerous tissues(P<0.05).Spearman rank correlation analysis showed that ALDH2 mRNA expression level was negatively correlated with the expression levels of CDCA2,DEPDC1,ESPL1,EXO1,FAM83D,FANCI,FOXM1,and HJURP in lung adenocarcinoma tissues(P<0.05).ALDH2 mRNA expression levels in lung adenocarcinoma tissues were positively correlated with the infiltration of B-lymphocytes,CD_(8)^(+)T-lymphocytes,CD_(4)^(+)T-lymphocytes,and dendritic cell and negatively correlated with the infiltration of macrophage and neutrophil(P<0.05).(2)Clinical trials results.The results of immunohistochemistry showed that the ALDH2 expression level in lung adenocarcinoma tissues was lower than that in paracarcinoma tissues(P<0.05).Among 55 patients with lung adenocarcinoma,30 cases survived and 25 cases died.The results of univariate Cox proportional risk regression analysis showed that age,tumour size,tumour stage,and ALDH2 expression level in lung adenocarcinoma tissues might be the influencing factors of the prognosis of patients with lung adenocarcinoma(P<0.05);the results of multivariate Cox proportional risk regression analysis showed that the tumour stage and ALDH2 expression level in lung adenocarcinoma tissues were the independent influencing factors of the prognosis of patients with lung adenocarcinoma(P<0.05).The patients were divided into the low expression group(28 cases)and the high expression group(27 cases)according to the median expression level of ALDH2(6.76)in lung adenocarcinoma tissue.Survival curve results showed that the survival rate of the low expression group was lower than that of the high expression group(P<0.05).Conclusion ALDH2 expression level reduces in lung adenocarcinoma tissues,the mechanism may be related to elevated levels of ALDH2 DNA methylation,mediation of cell-cycle signaling,and reshaping of tumor microenvironment.ALDH2 expression level in lung adenocarcinoma tissues is an independent influencing factor of the prognosis of patients with lung adenocarcinoma,and the patients with low ALDH2 expression have lower survival rate.