MiR-506 suppresses papillary thyroid carcinoma cell proliferation and metastasis via targeting IL17RD.

OBJECTIVE: The aim of this study was to determine the role of microRNA-506-3p (miR-506) in papillary thyroid carcinoma (PTC), and to further explore the underlying mechanism. PATIENTS AND METHODS: The expression level of miR-506 in clinical cases was detected by Real Time-fluorescence quantitative Polymerase Chain Reaction (RT-qPCR). Meanwhile, RT-qPCR was performed to determine miR-506 expression in different PTC cell lines. Bioinformatics software was used to predict the possible target genes of miR-506. Dual-Luciferase reporter gene assay together with Western blot (WB) assay were used to verify the prediction results. Finally, cellular functions such as proliferation and metastasis capacities were detected in vitro. RESULTS: RT-qPCR was used to measure the expression level of miR-506 in 80 paired PTC cases. The results showed that the expression level of miR-506 in PTC tissues was significantly decreased. In vitro, miR-506 expression was also markedly suppressed in four PTC cell lines. TPC-1 cells expressed the lowest level of miR-506. Subsequently, the target gene of miR506 was predicted by TargetScan, miRBase and miRanda. The prediction results indicated that IL17RD was an alternative target gene of miR-506. Furthermore, miR-506 was found to remarkably inhibit the Luciferase activity of wild-type IL17RD. However, it had no effect on mutant-type. Besides, the protein expression level of IL17RD was significantly reduced in miR-506-overexpressing TPC-1 cells. More importantly, the restored expression of IL17RD could alleviate the blocking effects of miR-506 on cell proliferation, migration and invasion. CONCLUSIONS: In this study, we found that miR-506 could inhibit the proliferation and metastasis of PTC cells. Meanwhile, IL17RD might be a downstream target of the biological process. Our findings provided a new therapeutic direction for the treatment of PTC.