Effects And Mechanism Of MiR-148b In Biological Behavior Of Pancreatic Cancer

Background and purpose:MicroRNAs (miRNAs) are small non-coding RNAs that participate in a variety of biological processes, and miRNAs are always associated with cancer development and progression, acting as tumor suppressors or oncogenes. Aberrant expression of miR-148b has been found in some types of cancer, but its expression and potential biological role in pancreatic cancer are still largely unknown.Methods:Quantitative real-time PCR was used to determine the level of miR-148b expression in human pancreatic cancer tissues and five cell lines, and its correlation with clinical characteristics was determined using χ2tests. Restoration of miR-148b expression was carried out in pancreatic cancer cell lines to assess its influence on cancer cell proliferation and tumourigenicity. Apoptosis and cell cycle were assessed by flow-cytometry assay. Cell invasion was assessed using the matrigel invasion assay. Luciferase activity assay was performed using the Dual-Luciferase Reporter Assay. miR-148b and AMPKα1siRNA on AMPKα1expression were detected by quantitative real-time PCR and western blot, AMPKα1expression was analyzed by quantitative real-time PCR and Immunohistochemistry in pancreatic cancer. Silencing of AMPKα1was carried out to assess its influence on cancer cell proliferation, apoptosis, cell cycle, cell invasion and tumourigenicity.Results:our data showed that miR-148b was significantly downregulated in48pairs of human pancreatic cancer tissues and five cell lines. Further, the deregulated miR-148b was correlated with tumor size, TNM stage, lymphatic invasion and distant metastasis in pancreatic cancer. Functional studies indicated overexpression of miR-148b dramatically suppressed the growth of cancer cells, attributable to induction of apoptosis and cell cycle arrest at S phase. Meanwhile, miR-148b remarkably inhibited invasion of pancreatic cancer cells. Moreover, ectopic expression of miR-148b was able to inhibit tumourigenicity in nude mice. Further studies revealed that miR-148b mimics significantly decreased the firefly luciferase activity of the reporter with wild type3’UTR of AMPKal, and decreased AMPKαl expression in mRNA and protein levels. Furthermore, AMPKαl was overexpressed and located primarily to cytoplasm, and inversely correlated with miR-148b in pancreatic cancer. Silencing of AMPKal with RNAi inhibited the growth of pancreatic cancer cells in vitro and in vivo, and also induced apoptosis, cell cycle arrest and inhibited invasion of cancer cells, which is consistent with the effects of miR-148b overexpression.Conclusions:miR-148b can inhibit cell proliferation and invasion of pancreatic cancer by targeting AMPKal, and play the negative regulatory role in the occurrence and development of pancreatic cancer. Our present results implicate targeted regulation of miR-148b may become a potential new target for pancreatic cancer.