Effect and Molecular Mechanism of MiR-181a-5p on the Proliferation and Invasion of Papillary Thyroid Cancer Cells

Objective To investigate the effect and regulation mechanism of miR-181a-5p on papillary thyroid carcinoma (PTC) cells.

Methods The expressions of miR-181a-5p and thyrotropin receptor (TSHR) in PTC tissues, and the targeting relationship between these two genes were analyzed using bioinformatics tools, and their relationship was verified by dual-luciferase reporter assay. After TPC-1 cells transfected with miR-181a-5p inhibitor and shTSHR, the expression levels of miR-181a-5p, TSHR, E-cadherin, N-cadherin and Vimentin were detected by quantitative reverse transcription polymerase chain reaction or western blot assay. The effects of miR-181a-5p and TSHR on the viability and invasion of TPC-1 cells were detected by MTT and Transwell assay.

Results The expression of miR-181a-5p was up-regulated in PTC tissues and cells (P<0.001), and the expression of TSHR was low in thyroid carcinoma tissues, and miR-181a-5p could directly target TSHR. Down-regulation of miR-181a-5p inhibited viability and invasion, and the expression of N-cadherin and Vimentin (P<0.01), but promoted the expression of E-cadherin in TPC-1 cells (P<0.001). TSHR knockdown produced the opposite result (P<0.01), and partially reversed the effect of miR-181a-5p downregulation on TPC-1 cells (P<0.01). Conversely, down-regulation of miR-181a-5p could reverse the effect of TSHR knockdown (P<0.05).

Conclusions Downregulation of miR-181a-5p inhibited the malignant progression of PTC cells by promoting the expression of TSHR.