Down-regulation of miR-26a-5p in hepatocellular carcinoma: A qRT-PCR and bioinformatics study

Background: To practically verify the clinical value of miR-26a-5p and thoroughly explore its target genes as well as its potential functions in hepatocellular carcinoma (HCC). Methods: HCC and adjacent non-cancerous hepatic tissues of 95 HCC patients were collected for analysis using reverse transcription quantitative real-time PCR (qRT-PCR). For the bioinformatics analysis, we identified potential target genes for miR-26a-5p from differentially expressed genes (DEGs) in Gene Expression Omnibus (GEO) data sets and miRWalk predicted database. Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and protein-protein interaction (PPI) analyses were applied to analyze the prospective mechanisms of the predicted target genes. Results: MiR-26a-5p showed a significantly lower expression level in HCC tissues (1.56 +/- 1.07) than adjacent benign liver tissues (2.28 +/- 1.06, P < 0.001). The area under the curve (AUC) of the receiver operating characteristic (ROC) was 0.665 (95% CI: 0.588-0.743, P < 0.001). Significant correlations between miR-26a-5p expression and clinicopathological features such as gender (r = 0.275, P < 0.01), clinical TNM stage (r = -0.306, P < 0.01), and metastasis (r = -0.321, P < 0.01) were observed. To examine potential target genes, we obtained 175 genes for further function analysis, by attaining the intersection of 2062 up-regulated DEGs and 1390 online-predicted target genes. The GO and KEGG pathway annotation indicated focal adhesion, regulation of actin cytoskeleton and the PI3K-Akt signaling pathway as significant prospective mechanisms. The PPI network indicated that NRAS was the most essential hub gene in the whole network. Conclusion: Down-regulated miR-26a-5p was closely correlated with the status of metastasis and the progression of HCC. MiR-26a-5p might play protective roles by targeting diverse genes and pathways.