Lower miR-1455 p expression and its potential pathways in hepatocellular carcinoma : a bioinformatics analysis with RNA-seq and microarray data

Background: The aim of our study was to investigate the clinical value of expression of miR-145-5p, and clarify its potential target genes and molecular function in hepatocellular carcinoma (HCC). Methods: Eleven microarray datasets containing 325 HCC and 319 non-cancerous liver tissues were extracted from the Gene Expression Omnibus (GEO) database to evaluate the expression level of miR-145-5p in HCC. Additionally, we also collected 354 HCC and 50 normal liver tissues from The Cancer Genome Atlas (TCGA) database to confirm the differentially expressed level of precursor miR-145 between HCC and normal liver tissues. Furthermore, the prospective target genes of miR-145-5p in HCC were predicted and the possible correlative signaling pathways were clarified. Results: MiR-145-5p was evidently decreased in HCC tissues according to the GEO datasets, which was also proved by the data from TCGA. Altogether, 144 genes were considered as the most likely target genes of miR-145-5p for HCC. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis clarified that the most enriched pathways included pathways in cancer, chronic myeloid leukemia and adherens junction. Nine hub genes (SMAD2, SMAD3, FOXO1, SMAD4, NRAS, MAPK1, SP1, MAPK9, CBL) with were screened out from the 144 genes, as evaluated by PPI network. Conclusions: The absence or down-regulation of miR-145-5p may play a pivotal role in the tumorigenesis of HCC. MiR-145-5p may influence the development of HCC via targeting multiple genes and pathways, which need to be further investigated.