Abstract: Background and purpose: The abnormally expressed miR-762 in various malignant tumors is involved in the proliferation, apoptosis, invasion and metastasis of tumors. Aim of the present study was to study the expression of miR-762 in pancreatic cancer tissues and cell lines and its effect on the proliferation, metastasis and invasion of pancreatic cancer cells. Methods: Real-time fluorescence quantitative polymerase chain reaction (RTFQ-PCR) was used to detect the expression of miR-762 mRNA in pancreatic cancer tissues who received radical resection of pancreatic cancer in the Fourth Hospital of Hebei Medical University and cell lines. The miR-762 mimics, miR-762 inhibitors and scramble sequences were transfected into PANC-1 cells with Lipofectamine ^TM 2000. The proliferation, apoptosis and migratory and invasive abilities of PANC-1 cells were detected with cell counting kit-8 (CCK-8) assay, flow cytometry, wound healing assay and Transwell assay. The expression of epithelial-mesenchymal transition (EMT) related markers were determined by Western blot. Results: The miR-762 expression was significantly up-regulated in pancreatic cancer tissues compared with paracancerous tissues (P<0.01). Similarly, miR-762 expressions of the four pancreatic cancer cell lines (BxPC-3, PANC-1, AsPC-1 and SW-1990) were significantly higher than those in the normal pancreatic ductal epithelial cells HPDE (P<0.01). miR-762 mRNA expression in PANC-1 cell line was obviously increased after transfection with miR-762 mimics, but markedly decreased after transfection with miR-762 inhibitors (P<0.01). Meanwhile, D ₄₅₀ , the healing rate, invasive cells and expressions of N-cadherin and vimentin proteins in miR-762 mimics group were significantly higher than those in negative control group after transfection, and apoptotic rate and E-cadherin protein expression were significantly lower than those in negative control group after transfection. D ₄₅₀ , the healing rate, invasive cells and expressions of N-cadherin and vimentin in miR-762 inhibitors group were significantly lower than those in negative control group after transfection, while apoptotic rate and E-cadherin expression were significantly higher than those in negative control group after transfection (P<0.05). Conclusion: The over-expression of miR-762 can effectively enhance the proliferation, metastasis and invasion ability in PANC-1 cells, in which EMT related markers including N-cadherin, vimentin and E-cadherin may play a role.

Key words:  Pancreatic cancer, miR-762, Proliferation, Invasion and metastasis