Abstract
The aberrant expression of microRNAs (miRNAs) has been found in various types of cancer and is associated with tumorigenesis and metastasis. However, the expression and function of miR-223 in nasopharyngeal carcinoma (NPC) remain unclear. The present study demonstrated that miR-223 was downregulated in NPC cell lines. The ectopic expression of miR-223 dramatically suppressed cell proliferation, invasion and epithelial-mesenchymal transition (EMT). Moreover, a luciferase reporter assay identified the structure-specific recognition protein (SSRP1) as a novel direct target of miR-223. SSRP1 expression was upregulated in NPC cell lines and the overexpression of miR-233 markedly reduced the expression of SSRP1. Furthermore, SSRP1 was involved in miR-223-regulated NPC cell proliferation, invasion, and EMT. Taken together, these results indicate that miR-223 functions as a tumor suppressor miRNA in NPC and that its suppressive effects are primarily mediated by repressing SSRP1 expression and inhibiting EMT.