To investigate the effect of miR-223 on thyroid cancer cells, further to study its potential mechanisms. The difference in miR-223 expression between normal thyroid Nthy-ori3-l cells and thyroid cancer SW579 cells was detected by PCR. The miR-223 overexpression and silencing vector transfection were verified by qRT-PCR. To further investigate the role of miR-223 in AQP-1, the AQP-1 siRNA vector was transfected on the basis of transfection of miR-223 inhibitor vector. The cell proliferation was detected by plate cloning, MTT, and cellular immunofluorescence assays. Cell cycle and apoptosis were detected by flow cytometry. Western blot was used to detect the expression of AQP-1 protein. The expression of miR-223 in SW579 cells was higher than that in normal cells. After transfection with miR-223 mimic, miR-223 expression was increased in SW579 cells. MiR-223 inhibitor transfection can inhibit SW579 cells proliferation, promote apoptosis, and inhibit cell cycle G0/G1 arrest. The SW579 cells proliferation was decreased, and the apoptosis rate was increased after transfection of AQP-1 silencing vector. Compared with the AQP-1 siRNA group, the SW579 cells proliferation rate was further reduced, and the apoptosis rate was significantly increased after co-transfection of miR-223 silencing vector and AQP-1 silencing vector. AQP-1 protein was highly expressed in SW579 cells, and miR-223 inhibitor can down-regulate the expression of APQ-1 protein. The expression AQP-1 protein was significantly reduced after transfected with AQP-1 silencing vector. Inhibition of miR-223 expression could suppress proliferation and promote apoptosis of SW579, and its mechanism is related to down-regulation of APQ-1 protein expression.
Keywords: Thyroid cancer cells; aquaporin-1; miR-223; proliferation.