Micro RNA-363 inhibits esophageal squamous cell carcinoma progression by directly targeting sperm-associated antigen 5

Objective Micro RNA (miR)-363 has many important biological functions in cancers, but its roles in esophageal squamous cell carcinoma (ESCC) remain unclear. Methods We used reverse transcription PCR to quantify the expression of miR-363 in 80 ESCC tissues and analyzed its relationship with clinicopathological factors and overall survival. The effects of miR-363 on cell proliferation, apoptosis, and invasion were detected using the MTT assay, flow cytometry, and Transwell invasion assays, respectively. Further, we investigated the post-transcriptional regulation of sperm-associated antigen 5 (SPAG5) expression by miR-363 using luciferase reporter assays. Finally, the effects of SPAG5 on miR-363 were studied by SPAG5 overexpression. Results miR-363 expression was decreased in both ESCC specimens and cell lines, compared with controls, and correlated with lymph node metastasis and tumor differentiation. Low miR-363 expression was identified as an independent prognostic factor for ESCC. miR-363 overexpression decreased ESCC cell proliferation and invasion and increased apoptosis, while the opposite was seen after miR-363 inhibition. Moreover, SPAG5 was identified as a direct target of miR-363, and the reintroduction of SPAG5 restored miR-363-induced effects. Conclusions miR-363 acts as a tumor suppressor by post-transcriptionally regulating SPAG5 expression, suggesting its potential as a diagnostic biomarker and therapeutic target for ESCC.