Abstract
MicroRNAs (MiRNAs) play critical roles in regulating target gene expression and multiple cellular processes in human cancer malignant progression. However, the function of miR-194 in gastric cancer (GC) remains unclear and controversial. In this study, we identified a series of miRNAs that can serve as prognostic biomarkers for GC by analysis of miRNA expression using The Cancer Genome Atlas data. Among them, miR-100, miR-125b, miR-199a, and miR-194 were the four most promising prognostic biomarkers in GC due to their significant associations with various clinical characteristics of patients. miR-100, miR-125b, and miR-199a predicted poor prognosis in GC, while miR-194 predicted favorable prognosis in GC. We also provide the first comprehensive transcriptome analysis of miR-194 in GC. Our data suggest that miR-194 tends to regulate target genes by binding to their 3' UTRs in a 7-mer-A1, 7-mer-m8, or 8-mer manner. KEGG pathway analysis showed that the cell cycle was one of the pathways most affected by miR-194 in GC. Moreover, CCND1 was shown to be a novel target gene of miR-194 in GC. Additionally, downregulation of CCND1 by miR-194 in GC further led to cell growth inhibition and cell cycle arrest. In conclusion, miR-100, miR-125b, miR-199a, and miR-194 may have potential as prognostic and diagnostic biomarkers for GC. miR-194 suppresses GC cell growth mainly through targeting CCND1 and induction of cell cycle arrest.