Exosomal miR-374c-5p derived from mesenchymal stem cells suppresses epithelial-mesenchymal transition of hepatocellular carcinoma via the LIMK1-Wnt/β-catenin axis.

Metastasis is a leading cause to treatment failure in hepatocellular carcinoma (HCC) patients. Exosomes act as pivotal mediators in communication between different cells and exert effects on recipient cells by delivering bioactive cargoes, such as microRNAs (miRNAs). MiRNAs function in multiple steps of HCC development, including metastasis. MiR-374c-5p was previously identified as a tumor suppressor in some malignancies, while the current knowledge of its role in HCC metastasis is still limited. Herein, miR-374c-5p was found to be downregulated in HCC cell lines and clinical samples, and positively related with favorable prognosis in HCC patients. MiR-374c-5p transferred by exosomes derived from bone marrow mesenchymal stem cell (BMSC) suppressed migration, invasion and proliferation of HCC cells. LIMK1 was verified as downstream target gene of miR-374c-5p. Knockdown of LIMK1 reduced invasion, migration and proliferation of HCC cells, whereas overexpression functioned oppositely. The miR-374c-5p/LIMK1 axis suppressed epithelial-mesenchymal transition (EMT) by inactivating Wnt/β-catenin pathway. In addition, miR-374c-5p was downregulated and LIMK1 upregulated in TGF-β1 induced EMT. This EMT model could be reversed by LIMK1 silencing or miR-374c-5p overexpression. These results suggest that exo-miR-374c-5p suppresses EMT via targeting LIMK1-Wnt/β-catenin axis and the axis is involved in TGF-β1 induced metastasis of HCC, thereby identifying miR-374c-5p as a potential target for HCC treatment.