Estimation of hub genes and exploration of multi-omics level alterations in the landscape of lung adenocarcinoma

OBJECTIVES: Lung adenocarcinoma (LUAD) is recognized as one of the most prevalent and deadliest malignancies around the globe. The molecular mechanisms behind LUAD have not been fully elucidated. This study was launched to explore LUAD-associated hub genes and their enriched pathways using bioinformatics methods.

METHODS: Information on GSE10072 was retrieved from the Gene Expression Omnibus (GEO) database and analyzed via the Limma package-based GEO2R tool to obtain the top 100 differentially expressed genes (DEGs) in LUAD. The protein-protein interaction (PPI) network of the DEGs was drawn using the STRING website and was shifted into Cytoscape to screen the top 6 hub genes via the CytoHubba application. Furthermore, the expression analysis and validation of hub genes in LUAD samples and cell lines were done using UALCAN, OncoDB, and GENT2 databases. Moreover, OncoDB was also used for analyzing hub gene DNA methylation levels. In addition, cBioPortal, GSEA tool, Kaplan-Meier (KM) plotter, Enrichr, CancerSEA, and DGIdb were performed to explore some other important aspects of hub genes in LUAD.

RESULTS: We identified Interleukin 6 (IL6), Collagen, type I, alpha 1 (COL1A1), TIMP metallopeptidase inhibitor 1 (TIMP1), CD34 molecule (CD34), Decorin (DCN), and Secreted Phosphoprotein 1 (SPP1) genes as the hub genes in LUAD, out of which IL6, CD34, and DCN were significantly down-regulated while COL1A1, TIMP1, and SPP1 were significantly up-regulated in LUAD cell lines and samples of diverse clinical variables. In this study, we also documented some important correlations between hub genes and other parameters such as DNA methylation, genetic alterations, Overall Survival (OS), and 14 important states at the single cell level. Lastly, we also identified hub genes associated with the ceRNA network and 11 important chemotherapeutic drugs.

CONCLUSION: We identified 6 hub genes involved in the development and progression of LUAD. These hub genes can also be helpful in the accurate detection of LUAD and provide novel ideas for treatment.