Down-regulation of miR-451 promotes invasion and proliferation of human osteosarcoma U2OS cells via RAB14-mediated AMPK-Akt-mTOR signaling pathway

MicroRNAs (miRNAs) have been reported function as tumor suppressors or oncogenes. Ectopic expression of miRNA may lead to dysfunction of cell biological behaviors. MiR-451 is down-regulated and functions as a tumor suppressor mediated by different signal pathways. However, the expression pattern and the regulation mechanism of miR-451 remain to be elucidated. Our results showed that miR-451 was frequently down-regulated in osteosarcoma tumor and cell lines. Over-expression of miR-451 in osteosarcoma cell line significantly inhibited cell proliferation and invasion, and promoted cell adhere to matrix by down-regulating Ras-related protein 14 (RAB14) expression. SiRNA mediated silencing of RAB14 phenocopied the over-expression of miR-451. Together, these findings demonstrated that miR-451 functions as a tumor suppressor via RAB14-mediated AMPK-AKT-mTOR signal pathway.