Abstract: Objective To investigate whether miR-205 can regulate wingless-type MMTV integration site family member 5a (Wnt-5a) to inhibit the papillary thyroid carcinoma (PTC) cell proliferation. Methods RT-qPCR was used to detect the expression of miR-205 and Wnt-5a in PTC tissues and adjacent normal tissues.Further correlation analysis between miR-205 and Wnt-5a was carried out. The low expression of miR-205 related to the stage of PTC TMN and lymph node metastasis was also discussed. Meanwhile, RT-qPCR was also used to detect NTHY-OR-3-1 and PTC cell lines (K1 and BCPAP). In addition, the proliferation of PTC cells was detected by CCK-8 after over expression and inhibition of miR-205. Xenograft tumor formation test was used to observe whether inhibition of miR-205 acceler- ates the growth of tumor. The online target gene prediction software and dual luciferase reporter gene test were used to predict and verify whether Wnt-5a is the target gene of miR-205. Results The expression of miR-205 was significantly lower than that of surrounding normal tissues, and the expression of Wnt-5a was significantly higher. TNM stage and lymph node metastasis severity of PTC patients were significantly higher in patients with low miR-205 expression than in patients with high miR-205 expression. Low expression of miR-205 showed a poor survival rate. Expression of miR-205 in NTHY-OR-3-1 was significantly lower than that of K1 and BCPAP. miR-205 inhibited the proliferation of PTC cells. Over-expression of miR-205 also inhibited the growth of PTC. It was confirmed that Wnt-5a was the target gene of miR-205 by luciferase reporter assay. Conclusions miR-205 plays an anti-cancer role in PTC, which may be a potential therapeutic target.

Key words: papillary thyroid carcinoma, miR-205, cell proliferation, Wnt-5a