MicroRNA-791 is an independent prognostic factor of papillary thyroid carcinoma and inhibits the proliferation of PTC cells.

OBJECTIVE: To investigate the significance and possible mechanism of miR-791 in the pathogenesis of papillary thyroid carcinoma (PTC).

PATIENTS AND METHODS: The expression of miR-791 in 80 cases of thyroid carcinoma tissues and 80 cases of paracancerous tissues was detected by quantitative Real-time-polymerase chain reaction (qRT-PCR). After miR-791 mimics were transfected into thyroid cancer cells by liposome method, the cell proliferation was detected by Cell Counting Kit-8 (CCK-8) and 5-ethynyl-2'-deoxyuridine (EDU), respectively. Cell cycle was detected by flow cytometry.

RESULTS: The expression of miR-791 in thyroid cancer tissue was significantly lower than that of normal thyroid. The mir-719 expression is positively correlated with the prognosis of thyroid carcinoma. After transfection of miR-791 mimics, the proliferation ability of TPC-1 and HTH83 cells was weakened, and the cell cycle was blocked in the G0/G1 phase. Further study on the underlying mechanism found that after overexpression of miR-791, the expressions of Cyclin D1, CKD6 and CDK4 decreased significantly, while the expression of cyclin inhibitor P21 increased significantly.

CONCLUSIONS: MiR-791 is lowly expressed in thyroid cancer. MiR-791 may inhibit thyroid cancer cell proliferation by blocking thyroid cancer cells in G0/G1 phase, thus participating in the impediment of thyroid cancer development.