Identification of hub genes associated with head and neck squamous cell carcinoma by integrated bioinformatics approach and RNA-seq validation analysis.

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.