EFNB2 acts as the target of miR-557 to facilitate cell proliferation, migration and invasion in pancreatic ductal adenocarcinoma by bioinformatics analysis and verification

This study aims to identify the pivotal microRNAs (miRNAs) and genes, and their potential regulatory mechanisms in pancreatic ductal adenocarcinoma (PDAC) through bioinformatics analysis and experimental verification. We comprehensively analyzed two miRNA microarray datasets (GSE32678 and GSE43796) and three gene microarray datasets (GSE28735, GSE41368 and GSE71989), which were downloaded from the Gene Expression Omnibus (GEO) database, and identified the total of 8 differentially expressed miRNAs (DEMs) and 257 differentially expressed genes (DEGs) in common. Next, a new miRNA-mRNA regulatory network was constructed by bioinformatics methods, including 7 miRNAs, 58 putative target genes and 80 interaction pairs of miRNA-mRNA. Scrutinized by OncoLnc and GEPIA, it was found that 3 of 7 miRNAs (miR-21, miR-196b and miR-203) and 20 of 58 genes (MXRA5, EPYC, ECT2, COL12A1, SLC6A14, SLC7A2, BTG2, PDK4, CTNND2, NRP2, PXDN, CD109, TGFBI, LRRN1, ITGA2, DKK1, GREM1, EFNB2, SEMA3C and NT5E) were notably associated with prognosis in patients with PDAC. Furthermore, EFNB2 was significantly upregulated in PDAC compared with normal controls from different public databases. Cellular function experiments demonstrated that EFNB2 knockdown inhibited cell proliferation, migration and invasion in SW1990 cells. Western blot and luciferase reporter assays revealed that miR-557 negatively regulated the expression of EFNB2 by directly binging its 3' UTR. In conclusion, we performed integrated analysis for multiple expression profiles, and provided novel candidate miRNAs and genes to be exploited for functional studies. In addition, our findings suggested that EFNB2 contributes to PDAC progression by acting as the target gene of miR-557. It is useful for uncovering miRNA-based treatments in PDAC.