MiR-223 inhibits the proliferation, invasion and EMT of nasopharyngeal carcinoma cells by targeting SSRP1

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.