Reduction of miR-29c enhances pancreatic cancer cell migration and stem cell-like phenotype

The hallmarks of pancreatic cancer are limitless replicative potential as well as tissue invasion and metastasis, leading to an extremely aggressive disease with shockingly high lethality. However, the molecular mechanisms underlying these characteristics remain largely unclear. Herein, we report the results of a differential miRNA expression screen that compared pancreatic cancer tissues and normal pancreatic tissues, where the pancreatic cancer tissues had highly downregulated miR-29c with relative Wnt cascade hyperactivation. MiR-29c directly suppressed the following Wnt upstream regulators: frequently rearranged in advanced T-cell lymphomas 2 (FRAT2), low-density lipoprotein receptor-related protein 6 (LRP6), Frizzled-4 (FZD4) and Frizzled-5 (FZD5). Furthermore, transforming growth factor-β (TGF-β) inhibited miR-29c expression, leading to Wnt activation. Significantly, our results were consistent with an important correlation between miR-29c levels and TGF-β hyperactivation and the activated Wnt cascade in human pancreatic cancer specimens. These findings reveal a novel mechanism for Wnt hyperactivation in pancreatic cancer and may suggest a new target for clinical intervention in pancreatic cancer.