Dysregulated microRNA-329 (miR-329) serves an important role in the progression of certain types of tumor. However, the exact function and mechanisms of miR-329 in papillary thyroid cancer (PTC) remain unknown. The present study investigated the function and mechanisms of miR-329 in regulating PTC cell progression. The results revealed that the expression of miR-329 was significantly downregulated in PTC tissues and cell lines compared with adjacent normal tissues and a human immortalized follicular cell line. miR-329 mimics notably decreased PTC cell proliferation, colony formation and WNT1 expression in vitro, as well as suppressing PTC tumor growth in vivo. In addition, luciferase assays determined that miR-329 was able to directly bind with the 3'untranslated region of WNT1. Furthermore, short interfering RNA-WNT1-induced downregulation of WNT1, which demonstrated similar effects to miR-329 overexpression. WNT1 overexpression rescued the tumor suppressive effects of miR-329 in PTC cells. The present study provided new insights into the role of miR-329 in PTC progression and suggests the potential application of miR-329 as a therapy for PTC.
Keywords: WNT1; microRNA-329; migration and invasion; papillary thyroid cancer; proliferation.