MicroRNA-183 is involved in cell proliferation, survival and poor prognosis in pancreatic ductal adenocarcinoma by regulating Bmi-1.

As a highly aggressive malignant disease, the prognosis of patients with pancreatic ductal adenocarcinoma (PDAC) is poor. Yet, the mechanisms underlying the progression of PDAC remain unclear. MicroRNAs (miRNAs) may be involved in various human cancers as cancer suppressors or oncogenes. MicroRNA-183 (miR-183) was recently reported to be dysregulated in various types of cancer and to play an important role in the processes of cancer. However, the effects and potential mechanisms of action of miR-183 in PDAC have not been explored. In the present study, low expression of miR-183 was observed in PDAC tissues and cell lines. Low expression of miR-183 in PDAC was significantly associated with tumor grade, metastasis and TNM stage. Kaplan-Meier survival analysis demonstrated that patients harboring low expression of miR-183 had a significantly reduced overall survival than patients with a high level of miR-183 expression. The present study revealed that B-cell-specific Moloney murine leukemia virus insertion site 1 (Bmi-1) expression was inversely correlated with miR-183. Our findings also demonstrated that a low level of miR-183 expression effectively suppressed the growth of PDAC cells via regulation of Bmi-1. Following Bmi-1 silencing or upregulation of miR-183, the expression levels of cyclin D1, cyclin-dependent kinase (CDK)2 and CDK4 were decreased. It is reasonable to conclude that alteration of miR-183 expression may regulate the function of PDAC cells by the downregulation of Bmi-1 expression.