Nigericin Suppresses the Wnt/β-catenin Signaling in Pancreatic Cancer through Targeting pre-miR-374b-PRKCA/HBP1 Axis

Background: The polyether antibiotic nigericin has been demonstrated recently to have anti-tumor activity in multiple cancers. But the biochemical basis for its anti-cancer effects has not been fully elucidated. The objective of this study was to investigate the potential mechanisms of nigericin in pancreatic cancer (PC) cells. Methods PC cells were exposed to increasing concentrations of nigericin at different time periods, and the corresponding IC50 values were calculated. Then the effects on the biological functions of PC cells were evaluated. Subsequent experiments including the high-throughput RNA sequencing, qRT-PCR, western blot, TOP/FOP-Flash reporter, Co-Immunoprecipitation and luciferase report assays were employed to reveal the potential mechanisms of nigericin. In addition, the inhibitory effects of nigericin on PC cells were also accessed in the subcutaneous tumor model. Results The data showed that nigericin was extremely sensitive to PC cells, and could influence the abilities of cell proliferation, colony formation, apoptosis, migration and invasion. The results in vitro implied that nigericin suppressed the Wnt/β-catenin signaling by up-regulating PRKCA and HBP1 mRNA expressions. Furthermore, the dual strands of pre-miR-374b were proved to down-regulate the PRKCA and HBP1 expressions coordinately, and over-expression of pre-miR-374b partly antagonized the suppressing effects of PC cells induced by nigericin. Meanwhile, the inhibitory effects of nigericin on PC cells were also confirmed in mice. Conclusion These findings demonstrated that suppressing the Wnt/β-catenin signaling pathway by targeting pre-miR-374b-PRKCA/HBP1 axis might represent a novel molecular mechanism of nigericin in PC. Nigericin remained a candidate for a potential pre-clinical application for PC.