MicroRNA-126 inhibits proliferation and metastasis in prostate cancer via regulation of ADAM9

The aberrant expression of microRNAs (miRs) has been identified to serve a crucial role in tumor progression. The present study aimed to evaluate the role of miR-126 in human prostate cancer (PCa). Firstly, miR-126 expression in prostate cancer tissues and cell lines was analyzed. A luciferase reporter assay and a rescue assay were performed, which identified ADAM metalloproteinase domain 9 (ADAM9) as the target gene of miR-126. Subsequently, Kaplan-Meier and log-rank analyses were used to investigate the association between ADAM9 expression and PCa prognosis. The results revealed that miR-126 expression was significantly downregulated in PCa tissues and cell lines. miR-126 overexpression was demonstrated to reduce PCa cell proliferation and metastasis, and to reverse the epithelial-mesenchymal transition process in vitro. In addition, as the target gene of miR-126, the upregulation of ADAM9 reestablished cell functions, including cell proliferation, migration and invasion. Patients with high ADAM9 expression levels exhibited a shorter biochemical recurrence-free survival time. In summary, miR-126 serves a role in the proliferation and metastasis of PCa cells, indicating that miR-126 and ADAM9 may represent potential biomarkers in the progression of advanced PCa, in addition to therapeutic targets.