Micro RNA-373 is down-regulated in pancreatic cancer and inhibits cancer cell invasion.

Abstract

Micro RNAs (miRNAs) are small noncoding RNAs that have gained attention as key molecules in the malignant characteristics of cancers, and several recent investigations also have identified some miRNAs as potential key regulators to inhibit the malignant characteristics of tumors. MiRNA-373 (miR-373) has recently been reported to induce E-cadherin, which is a key regulator of epithelial-mesenchymal transition (EMT). However, the role of miR-373 in the characteristics of cancer cells is not still well known. We investigated the expression levels of miR-373 in pancreatic cancer cell lines and its effect on the invasiveness of pancreatic cancer by using in vitro and in vivo models. We also analyzed the expression of miR-373 using formalin-fixed paraffin-embedded (n = 152) and microdissected frozen (n = 57) samples from pancreatic tissues. The levels of miR-373 expression were low in pancreatic cancer cell lines. In formalin-fixed paraffin-embedded and microdissected frozen samples, miR-373 expression was significantly down-regulated in pancreatic cancer compared with that in healthy pancreas (P < 0.001 and P = 0.005, respectively). We also found that reexpression of miR-373 repressed transforming growth factor-β-induced EMT, leading to inhibition of invasiveness of cancer cells. Furthermore, reexpression of miR-373 significantly inhibited peritoneal dissemination in vivo (P < 0.001). MiR-373 is down-regulated in pancreatic cancer, and its reexpression represses the invasiveness of pancreatic cancer cells.