RESUMO
Head and neck squamous cell carcinoma (HNSC) is one of the most lethal malignancies around the globe. Due to its complex nature, the diagnostic and prognostic signatures of HNSC remain poorly understood. This study was launched to identify signature genes and their signaling pathways related to the development of HNSC. In the current study, we retrieved the GSE53819 dataset from the Gene Expression Omnibus (GEO) database to determine the differentially expressed genes (DEGs) using the "Limma" R package. Adjusted P values P < 0.05 and |logFC| ≥ 1 were selected as the filtering conditions. To identify hub genes, the protein-protein interaction (PPI) network construction of the DEGs was performed using STRING. We further used UALCAN, GEPIA, OncoDB, GENT2, MEXPRESS, and HPA databases for the expression, validation, survival, and methylation analyses of the hub genes. The cBioPortal tool was used to investigate the genetic alterations in hub genes. CancerSEA, TIMER, DAVID, ENCORI, and DrugBank were also used to explore a few more hub gene-associated parameters. Lastly, HOK, FaDu, and SCC25 cell lines were used to validate hub gene expression via RNA sequencing (RNA-seq) technique. A total of top 250 DEGs were selected for detailed analysis in this study. From these DEGs, prognostic and diagnostic associated four hub genes, which could serve as potential molecular biomarkers and therapeutic targets in HNSC patients were identified. Four hub genes, including down-regulated DNAH1 and DNALI1, while up-regulated DNAH9 and CCDC151 were strongly implicated in HNSC. We also validated the same expression pattern of the hub genes using RNA-seq analysis in HNSC and normal cell lines. Moreover, this study also revealed some novel links between DNAH1, DNALI1, DNAH9, and CCDC151 expression and genetic alterations, promoter methylation status, immune cell infiltration, miRNAs, gene enrichment terms, and various chemotherapeutic drugs. In conclusion, we indicated four hub genes (DNAH1, DNALI1, DNAH9, and CCDC151) and their associated signaling pathways, which may improve our understanding of HNSC and could be used as new therapeutic targets.
RESUMO
Head and neck squamous cell carcinoma (HNSC) is the 6th most common cancer around the globe; its underlying molecular mechanisms and accurate molecular markers are still lacking. In this study, we explored hub genes and their potential signaling pathways through which these genes participate in the development of HNSC. The GSE23036 gene microarray dataset was attained from the GEO (Gene Expression Omnibus) database. Hub genes were identified via the Cytohubba plug-in application of the Cytoscape. The Cancer Genome Atlas (TCGA) datasets and cell lines (HOK and FuDu) were used to evaluate expression variations in the hub genes. Moreover, promoter methylation, genetic alteration, gene enrichment, miRNA network, and immunocyte infiltration analysis were also performed to confirm the oncogenic role and biomarker potential of the hub genes in HNSC patients. Based on the hub gene analysis results, four hub genes, including KNTC1 (Kinetochore Associated 1), CEP55 (Centrosomal protein of 55 kDa), AURKA (Aurora A Kinase), and ECT2 (Epithelial Cell Transforming 2), with the highest degree scores were denoted as hub genes. All these four genes were significantly up-regulated in HNSC clinical samples and cell lines relative to their counterparts. Overexpression of KNTC1, CEP55, AURKA, and ECT2 was also associated with poor survival and various clinical parameters of the HNSC patients. Methylation analysis through targeted bisulfite sequencing of HOK and FuDu cell lines revealed that the overexpression of KNTC1, CEP55, AURKA, and ECT2 hub genes was due to their promoter hypomethylation. Moreover, higher expressions of KNTC1, CEP55, AURKA, and ECT2 were positively correlated with the abundance of the CD4+ T cells and macrophage while with the reduction of CD8+ T cells in HNSC samples. Finally, gene enrichment analysis showed that all hub genes are involved in "nucleoplasm, centrosome, mitotic spindle, and cytosol" pathways. In conclusion, the KNTC1, CEP55, AURKA, and ECT2 genes could be potential biomarkers for HNSC patients and provide a novel insight into the diagnosis and treatment of the disease.