MicroRNA-494 acts as a tumor suppressor in pancreatic cancer, inhibiting epithelial-mesenchymal transition, migration and invasion by binding to SDC1

Pancreatic cancer (PC) is the fourth most common cause of cancer-related mortality in the industrialized world. Emerging evidence indicates that a variety of microRNAs (miRNAs or miRs) are involved in the development of PC. The aim of the present study was to elucidate the mechanisms through which miR-494 affects the epithelial-mesenchymal transition (EMT) and invasion of PC cells by binding to syndecan 1 (SDC1). PC tissues and pancreatitis tissues were collected, and the regulatory effects of miR-494 on SDC1 were validated using bioinformatics analysis and a dual-luciferase report gene assay. The cell line with the highest SDC1 expression was selected for use in the following experiments. The role of miR-494 in EMT was assessed by measuring the expression of SDC1, E-cadherin and vimentin. Cell proliferation was assessed using a cell counting kit (CCK)-8 assay, migration was measured using a scratch test, invasion was assessed with a Transwell assay and apoptosis was detected by flow cytometry. Finally, a xenograft tumor model was constructed in nude mice to observe tumor growth in vivo. We found that SDC1 protein expression was significantly higher in the PC tissues. SDC1 was verified as a target gene of miR-494. The SW1990 cell line was selected for use in further experiments as it had the lowest miR-494 expression and the highest SDC1 expression. Our results also demonstrated that miR-494 overexpression and SDC1 silencing significantly decreased the mRNA and protein expression of SDC1 and vimentin in SW1990 cells, while it increased E-cadherin expression and apoptosis, and inhibited cell growth, migration, invasion and tumor growth. On the whole, the findings of this study demonstrated that miR-494 is able to downregulate SDC1 expression, thereby inhibiting the progression of PC. These findings reveal a novel mechanism through which miR-494 affects the development of PC and may thus provide a basis for the application of miR-494 in pancreatic oncology.