Role of DNA methylation regulation of miR-130b expression in human lung cancer using bioinformatics analysis

MicroRNAs (miRNAs) are involved in various crucial biological processes including regulation of cell differentiation, proliferation, and migration, and are closely associated with tumor development. This study aimed to investigate miR-130b expression levels in lung cancer patient tissues. Two Gene Expression Omnibus (GEO) databases, including GSE48414 and GSE74190, and two The Cancer Genome Atlas (TCGA) databases including TCGA LUAD and TCGA LUSC, were accessed to obtain information for differential expression analysis and clinical-pathological correlation analysis. The results showed that miR-130b expression levels were significantly increased in lung cancer compared to normal tissues. Data also demonstrated that confounding factors such as tumor clinical stages and tumor invasion depth markedly affected miR-130b expression levels in cancer patients. A total of 169 target genes modified by miR-130b expression were identified by using 4 online websites for target gene prediction. Further enrichment analysis indicated that these 169 target genes were significantly enriched in several cancer-related biological processes and signaling pathways, including wound healing, cell proliferation, Wnt signaling, Ras signaling, and mTOR signaling. It was also of interest to examine the seven sites on the promoter region of miR-130b encoding gene in lung cancer patients and then compare methylation at these loci with miR-130b expression. The correlation analysis between encoding gene methylation and miR-130b expression in TCGA datasets revealed that decreased methylation in the promoter region was significantly associated with elevated miR-130b expression. This phenomenon was markedly dependent upon smoking history and clinical-pathological features. In conclusion, data indicated alterations in the methylation of DNA promoter region of miR-130b encoding gene were associated with disturbances in miR-130b expression in lung cancer patients suggesting that the DNA methylation process and miR-130b expression may serve as biomarkers for detection of lung cancer.