Abstract
Previously we found that melanoma-associated antigen-A9 (MAGE-A9) was a significantly upregulated biomarker in laryngeal squamous cell carcinoma (LSCC). A high expression of MAGE-A9 indicates an unfavorable survival outcome, and the MAGE-A9 expression level is an independent prognostic factor of LSCC. To explore the mechanism of MAGE-A9 upregulation, several predicted regulatory microRNAs were screened and validated in LSCC cells. In the current study, we found that miR-143-3p (MAGE-A9 related miRNAs) expression levels correlated negatively with the MAGE-A9 protein expression in LSCC tissues. Dual-luciferase reporter assays and Western blot analysis revealed MAGE-A9 to be a direct target of miR-143-3p. Furthermore, a series of in vitro gain- and loss-of-function assays revealed that miR-143-3p inhibited LSCC cell proliferation, migration, and invasion. Also, miR-143-3p suppressed LSCC tumorigenesis in vivo. These effects were clinically relevant, as a lower expression of miR-143-3p occurred in severer clinical stages and represented poor overall survival in patients with LSCC. Taken together, these results suggest that downregulation of miR-143-3p contributes to tumor progression through upregulation of MAGE-A9. The expression level of these two key molecules maintained LSCC progression, thus, highlighting the potential of miR-143-3p as a therapeutic target for human LSCC.