The microRNA expression signature of pancreatic ductal adenocarcinoma by RNA sequencing: anti-tumour functions of the cluster.

We analysed the RNA sequence-based microRNA (miRNA) signature of pancreatic ductal adenocarcinoma (PDAC). Aberrantly expressed miRNAs were successfully identified in this signature. Using the PDAC signature, we focused on 4 clustered miRNAs, , , and on human chromosome 2p16.1. All members of the cluster were significantly reduced in PDAC specimens. Ectopic expression of these miRNAs suppressed cancer cell aggressiveness, suggesting cluster as anti-tumour miRNAs in PDAC cells. The impact of (passenger strand of pre-) on cancer cells is still ambiguous. Forkhead box Q1 () was directly regulated by and overexpression of was confirmed in clinical specimens. High expression of predicted a shorter survival of patients with PDAC by Kaplan-Meier analysis. Loss-of-function assays showed that cancer cell migration and invasion activities were significantly reduced by si transfectants. We investigated pathways downstream from by using genome-wide gene expression analysis. Identification of the -mediated network in PDAC should enhance understanding of PDAC aggressiveness at the molecular level.