miR-499a promotes PANC-1 cell proliferation by down-regulating PDCD4 expression in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive digestive system tumors, but study of the molecular mechanism of occurrence and development of PDAC is considerably limited. In order to better understand the potential pathogenesis, the differentially expressed miRNAs were screened in PDAC and adjacent tissues using miRNAs microarrays. We found that miR-499a was significantly up-regulated in PDAC tissues compared with adjacent tissues, and protein-protein interaction (PPI) and gene ontology (GO) analyses indicated programmed cell death protein 4 (PDCD4) is a key target gene of miR-499a, which is involved in the regulation of transcription, cellular biosynthetic process, RNA metabolic process, and other multiple biologic processes. Moreover, PDCD4 mRNA and protein expression were obviously down-regulated in PDAC tissues compared with adjacent tissues. In vitro, up-regulating of miR-499a could decrease PDCD4 expression and promote cell proliferation in PANC-1 cells transfected with miR-499a mimics. Similarly, promoting proliferation was also observed in PANC-1 cells transfected with PDCD4 siRNA. In conclusion, we first found miR-499a was significantly up-regulated in PDAC tissues, and we promoted PANC-1 cell proliferation by down-regulating PDCD4 expression.