Impact of microRNA-21-5p on the growth of thyroid cancer cells via targeting the recombinant sclerostin domain containing protein 1.

OBJECTIVES: To explore the molecular mechanism for thyroid cancer metastasis via analyzing the role of microRNA (miR)-21-5p and its target gene recombinant sclerostin domain containing protein 1 (SOSTDC1) in thyroid cancer. METHODS: The target miR-21-5p was screened through bioinformatics analysis and cell verification, and the thyroid cancer cell lines was transfected with miR-21-5p inhibitor. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) test, flow cytometry, and cell scratch test were used to detect the proliferation, apoptosis and migration of thyroid cancer cells in the miR-21-5p inhibitor group and the inhibitor control group, respectively. The luciferase report experiment was used to verify the relationship between miR-21-5p and SOSTDC1, Western blotting was used to detect the expression levels and phosphorylation levels of SOSTDC1,phosphatidylinositol 3 kinase (PI3K), protein kinase B (Akt) and mitogen-activated protein kinases (MAPK), extracellular regulated protein kinases (ERK) in thyroid cancer cells. RESULTS: MiR-21-5p was significantly increased in thyroid cancer cells,which was negatively correlated with SOSTDC1 (r=-0.24, P<0.01). The proliferation and migration of thyroid cancer cells in the miR-21-5p inhibitor group was significantly lower than that in the inhibitor control group (both P<0.01), and the apoptosis rate in the miR-21-5p inhibitor group was significantly higher than that in the inhibitor control group (P<0.01).The luciferase report experiment showed that miR-21-5p could target and regulate the expression level of SOSTDC1, and the expression of PI3K in the miR-21-5p inhibitor group was significantly lower than that in the inhibitor control group (P<0.01). There were no significant changes in Akt and ERK1/2 levels, but the phosphorylation levels of Akt and ERK1/2 in the miR-21-5p inhibitor group were significantly lower than those in the inhibitor control group (both P<0.01). CONCLUSIONS: MiR-21-5p in thyroid cancer cells can target the expression of SOSTDC1 and affect the activities of PI3K/Akt and MAPK/ERK, thereby inhibiting the apoptosis of thyroid cancer cells and promoting cell proliferation and migration.