Abstract: Objective To investigate whether miR-197-3p affects the proliferation, migration and invasion of thyroid cancer cells through regulation of deletion of malignant brain tumors 1(DMBT1) expression. Methods The expression of miR-197-3p in human normal thyroid cells Nthy-ori 3-1 and thyroid cancer cell lines SW579 and CGTHW-1 was detected by RT-qPCR,MTT assay was used to detect the proliferation of SW579 cells, and Transwell chamber assay was used to detect the migration and invasion of SW579 cells, the dual luciferase reporter gene assay verified whether miR-197-3p targets DMBT1, and the expression of DMBT1, cyclin D1, p21, MMP-2and E-cadherin in the cells was detected by Western blot. Results Compared with Nthy-ori 3-1 cells, the relative expression of miR-197-3p was increased in SW579 and CGTHW-1 cells (P＜0.05). After inhibiting the expression of miR-197-3p, the proliferation, migration and invasion of SW579 cells were significantly inhibited, and the expression of cyclin D1 and MMP-2 proteins was decreased and the expression of p21 and E-cadherin proteins was increased. miR-197-3p targeting negatively regulates DMBT1 expression in SW579 cells. Over-expression of DMBT1 significantly inhibited the proliferation, migration and invasion of SW579 cells, while inhibition of DMBT1 reversed the effect of miR-197-3p on proliferation, migration and invasion of SW579 cells. Conclusions miR-197-3p inhibits the proliferation, migration and invasion of thyroid cancer cell regulation of DMBT1 expression.

Key words: thyroid cancer cell, miR-197-3p, DMBT1, proliferation, migration