Deregulation of the MiR-193b-KRAS Axis Contributes to Impaired Cell Growth in Pancreatic Cancer

Modulation of KRAS activity by upstream signals has revealed a promising new approach for pancreatic cancer therapy; however, it is not clear whether microRNA-associated KRAS axis is involved in the carcinogenesis of pancreatic cancer. Here, we identified miR-193b as a tumor-suppressive miRNA in pancreatic ductal adenocarcinoma (PDAC). Expression analyses revealed that miR-193b was downregulated in (10/11) PDAC specimens and cell lines. Moreover, we found that miR-193b functioned as a cell-cycle brake in PDAC cells by inducing G1-phase arrest and reducing the fraction of cells in S phase, thereby leading to dampened cell proliferation. miR-193b also modulated the malignant transformation phenotype of PDAC cells by suppressing anchorage-independent growth. Mechanistically, KRAS was verified as a direct effector of miR-193b, through which the AKT and ERK pathways were modulated and cell growth of PDAC cells was suppressed. Taken together, our findings indicate that miR-193b-mediated deregulation of the KRAS axis is involved in pancreatic carcinogenesis, and suggest that miR-193b could be a potentially effective target for PDAC therapy.