基于数据挖掘分析低氧诱导因子-3α在头颈鳞状细胞癌中的表达及临床意义

The expression and clinical significance of hypoxia-inducible factor-3α in head and neck squamous cell carcinoma based on data analysis

目的探讨头颈鳞状细胞癌(HNSCC)患者中低氧诱导因子-3α(HIF-3α)的表达与其DNA甲基化水平的关系,研究HIF-3α表达异常对HNSCC患者预后的影响。方法以肿瘤基因组(TCGA)数据库为研究基础,分析HIF-3α在530例HNSCC及50例正常头颈组织中的mRNA表达及DNA甲基化水平,独立样本t检验进行统计分析;Pearson相关性分析HNSCC组织中HIF-3αDNA甲基化水平与其m RNA表达之间的关系。Kaplan-Meier生存分析法研究HIF-3α表达与HNSCC患者的总生存率及无复发生存率之间的关系,Log-rank检验进行统计分析。对HIF-3α高表达组与低表达组肿瘤组织进行差异表达基因分析,同时对差异表达基因进行基因富集分析(GSEA),研究其可能参与的生物学功能。结果与正常组织相比,HNSCC组织中HIF-3α的mRNA表达水平降低,表达量分别为(4.809±0.293)和(3.100±0.092),差异有统计学意义(t=5.369,P<0.001);而DNA甲基化水平升高,表达量分别为(0.158±0.010)和(0.362±0.009),差异有统计学意义(t=6.806,P<0.001);HNSCC组织中HIF-3α的m RNA表达水平与其DNA甲基化水平呈负相关(r=-0.46,P<0.001);HIF-3α低表达的HNSCC患者总生存率及无复发生存率均显著低于HIF-3α高表达组(HR=0.701,P=0.02;HR=0.517,P=0.004);GSEA基因富集分析发现,HIF-3α低表达组和高表达组差异基因主要富集在P53信号通路、凋亡通路和免疫反应通路。互作蛋白分析显示,HIF-3α可能与血管内皮生长因子A(VEGFA)、CREB结合蛋白(CREBBP)等相互作用。结论 HIF-3α在HNSCC中表达降低与其DNA甲基化水平升高密切相关,是潜在的预后预测分子指标。

ObjectiveTo investigate the relationship between the hypoxia inducible factor-3α(HIF-3α)mRNA level and the DNA methylation level in patients with head and neck squamous cell carcinoma(HNSCC),and to identify the potential novel prognostic biomarker for HNSCC patients.MethodsBased on TCGA database,530 cases of HNSCC and 50 cases of normal tissue were analyzed for the mRNA and methylation level of HIF-3α with Independent sample t-test. Pearson correlation analysis was used to explore the relationship between DNA methylation and mRNA expression of HIF-3α.Kaplan-Meier survival curves were drawn to investigate the relationship between the expression of HIF-3α,the overall and recurrence-free survival rate of patients with HNSCC by using the Log-rank test. Thedifferentially expressed genes were detected in both the high-and low-expression groups of HIF-3α. Geneset enrichment analysis(GSEA)was performed to investigate the potential molecular function of HIF-3αin HNSCC. The online tool c Bioportal was used to examine the proteins that interacted with HIF-3α.ResultsThe m RNA expression level of HIF-3α in the normal tissue(4.809 ± 0.293)was significantlyhigher than that of HNSCC(3.100 ± 0.092;t = 5.369,P<0.001),whereas the DNA methylation level ofHIF-3α in the normal tissue(0.158 ± 0.010)was significantly lower than the latter(0.362 ± 0.009;t =6.806,P<0.001). Furthermore,the expression of HIF-3α m RNA was negatively correlated to the level ofDNA methylation in HNSCC tissue(r =-0.46,P<0.001). GSEA analysis showed that the differentiallyexpressed genes were mainly concentrated in P53 signaling pathway,apoptotic pathway and immuneresponse pathway. Interaction protein analysis showed that HIF-3α might interact with VEGFA andCREBBP.ConclusionsThe decrease of HIF-3α expression was strongly related to the increase of DNAmethylation in HNSCC. Patients with a low expression level of HIF-3α showed poor clinical outcomes,demonstrating that HIF-3α may be used as a prognostic indicator for HNSCC patients.