miR-429 suppresses tumor migration and invasion by targeting CRKL in hepatocellular carcinoma via inhibiting Raf/MEK/ERK pathway and epithelial-mesenchymal transition.

Tumor metastasis is one of the main causes of hepatocellular carcinoma (HCC) high mortality. CRKL (v-crk sarcoma virus CT10 oncogene homologue (avian)-like) play important roles in tumor metastasis, however, the exact role and underlying mechanism of CRKL in HCC is still unknown. In our study, we demonstrated miR-429 negatively regulated CRKL expression via selectively binding to CRKL-3'-UTR at 3728-3735 bp site by post-transcriptionally mediating its functionality. Re-expression and silencing of miR-429 was remarkably effective in suppressing and promoting HepG2 cell migration and invasion in vitro. Knockdown or overexpression of CRKL exhibited similar effects as the overexpression or silencing of miR-429, whereas, CRKL overexpression (without the 3'-UTR) abrogated miR-429-induced inhibition on HepG2 migration and invasion. Moreover, miR-429-CRKL axis affected HepG2 migration and invasion potentials by regulating the adhesion ability, cytoskeleton F-actin expression and arrangement of HepG2. Furthermore, interference of Raf/MEK/ERK pathway and EMT contributed to miR-429-CRKL axis mediated metastasis inhibition. Nevertheless, miR-429 could not inhibit HepG2 proliferation through CRKL/c-Jun pathway. Taken together, our data demonstrated that miR-429 might function as an antimetastatic miRNA to regulate HCC metastasis by directly targeting CRKL via modulating Raf/MEK/ERK-EMT pathway. The newly identified miR-429-CRKL axis represents a novel potential therapeutic target for HCC treatment.