Comprehensive analysis of miRNA expression profiles in IDA, IPMA, IPMC and cancer cell line

This study identified differentially expressed miRNAs exclusively in invasive ductal adenocarcinoma. The epithelial-mesenchymal transition (EMT) is a critical step for pancreatic cancer cells as an entry of metastatic disease. Wide variety of cytokines and signaling pathways are involved in this complex process while the entire picture is still cryptic. Recently, miRNA was found to regulate cellular function including EMT by targeting multiple mRNAs. We performed comprehensive analysis of miRNA expression profiles in invasive ductal adenocarcinoma (IDA), intraductal papillary mucinous adenoma (IPMA), intraductal papillary mucinous carcinoma (IPMC) and human pancreatic cancer cell line to elucidate essential miRNAs which regulate invasive growth of pancreatic cancer cells. Along with higher expression of miR-21 which has been shown to be highly expressed in IDA, reduced expression of miR-126 in IDA and pancreatic cancer cell line was detected. Re-expression of miR-126 in pancreatic cancer cells resulted in reduced cellular migration, invasion and induction of epithelial marker E-cadherin. We demonstrated for the first time that the miR-126 plays essential role in the inhibition of invasive growth of pancreatic cancer cells. The expression profile of miRNA in each sample or cell line was evaluated by microarray and cluster analysis was performed.