Diagnostic and biological significance of microRNA-192 in pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal types of human cancer. In the present study, we evaluated serum microRNA-192 (miR-192) as a potential biomarker in patients with PDAC and investigated its biological functions in this disease. miRNA expression profiling of human PDACs and adjacent normal pancreatic tissues identified 16 upregulated miRNAs including miR-192 and 8 downregulated miRNAs. Quantitative real-time polymerase chain reaction (PCR) revealed elevation of serum miR-192 levels in PDAC patients relative to these levels in duodenal adenocarcinoma patients and healthy controls. Receiver operating characteristic analysis demonstrated that serum miR-192 had a sensitivity of 76% and a specificity of 55% for detecting PDAC. Ectopic expression of miR-192 in PANC-1 pancreatic cancer cells enhanced cell proliferation and migration, reduced apoptosis and promoted cell cycle progression from the G0/G1 to the S phase. Western blot analysis showed that enforced expression of miR-192 decreased the expression of smad-interacting protein 1 (SIP1) and altered a set of cell cycle-related genes in the PANC-1 cells. miR-192 overexpression increased tumor volume in an orthotopic pancreatic cancer mouse model, coupled with suppression of SIP1 and elevation of collagen I. In conclusion, serum miR-192 may serve as a sensitive diagnostic biomarker for PDAC. Overexpression of miR-192 contributes to tumor growth and progression in PDAC, which is associated with repression of SIP1 and alteration of cell cycle regulatory genes.