Identification of the key miRNA-mRNA regulatory network in lung adenocarcinoma

Background: Lung adenocarcinoma (LUAD) is the most common type of lung cancer, has a high incidence rate and is a serious threat to human health. However, the pathogenesis of LUAD is still unclear. Further research on the pathogenesis of LUAD may provide targets for the early diagnosis and treatment of LUAD. Methods: First, a transcriptome analysis was conducted to sequence the messenger RNA (mRNA) and micro RNA (miRNA) of the LUAD and adjacent control tissues. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were then performed for the functional annotation. Next, a differential miRNA-differential mRNA regulatory network was then constructed, and the function of the mRNAs in the network was analyzed and the key regulatory molecules (the hub molecules) were identified. Cytohubba was then used to analyze the top 20 hub molecules in the total miRNA-mRNA network, and the miRNAs regulating the top 20 hub genes (of which 2 were upregulated and 18 were downregulated). Finally, the key molecules were identified. Results: By analyzing the function of the mRNA molecules in the regulatory network, we found that the immune response was inhibited, as were the movement and adhesion of immune-related cells; however, cell tumorigenesis, body death, and tumor cell proliferation were activated. The functions of the 20 hub molecules were mainly related to cytotoxicity, cell exosmosis, and cell adhesion mediated by immune cells. Further, we found that miR-5698, miR224-5p, and miR4709-3P regulate multiple key genes (e.g., PECAM1, CX3CR1, KLRD1, and CXCL12), and may be the key miRNAs regulating LUAD. Conclusions: Immune response, cell tumorigenesis, and tumor cell proliferation play central roles in the overall regulatory network. miR-5698, miR224-5p, and miR4709-3p may be important biomarkers for the occurrence and development of LUAD and have great potential in the prognosis of LUAD patients and the development of new therapeutic targets.