MicroRNA-550a Acts as a Pro-Metastatic Gene and Directly Targets Cytoplasmic Polyadenylation Element-Binding Protein 4 in Hepatocellular Carcinoma

<div><p>MicroRNAs (miRNAs) are a class of small, non-coding RNA molecules that are often found at chromosomal breakpoints and play a vital role in human cancer. Our previous study found that miR-550a, a frequently amplified miRNA on 7p14.3, was upregulated in hepatocellular carcinoma (HCC). However, the possible functions and molecular mechanisms of miR-550a in HCC remain unknown. In this study, gain-of-function and loss-of-function assays revealed that miR-550a markedly promoted HCC cell migration and invasion. In addition, we discovered that cytoplasmic polyadenylation element binding protein 4 (<em>CPEB4</em>) was a potential target of miR-550a in HCC. Further analyses showed that knockdown of <em>CPEB4</em> expression significantly facilitated HCC cell migration and invasion, which phenocopied the effects of miR-550a on HCC cells. Moreover, a decrease in <em>CPEB4</em> expression mediated miR-550a-induced liver cancer cell migration and invasion. Interestingly, <em>CPEB4</em> is frequently downregulated in HCC, and its expression levels correlate with the overall survival of HCC patients. Together, these results suggested that this newly identified miR-550a-<em>CPEB4</em> axis may be involved in HCC cell metastasis. Moreover, the expression levels of <em>CPEB4</em> could be used to predict outcomes in HCC patients. Our findings provide novel potential targets for HCC therapy and prognosis.</p>