Baicalein inhibits cell development in papillary thyroid cancer by regulating miR-206/RAP1B pathway

Purpose: To investigate the therapeutic effect of baicalein on papillary thyroid cancer (PTC) cells in vitro and its underlying molecular mechanism.Methods: The human PTC cell line TPC-1 was divided into five groups and treated with distilled water or baicalein at 10, 20, 50, or 100 μM. Next, miR-206, miR-206 inhibitor, the respective negative controls of miR-206 and miR-206 inhibitor, RAP1B small interfering RNA (siRNA), and control vector siRNA were synthesized and transfected into TPC-1 cells. Cell viability, migration, and invasion were measured using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) and Transwell assays. miR-206 expression and Ras-related protein (RAP1B) levels were assessed by quantitative real-time reverse transcription-polymerase chain reaction and western blotting, respectively.Results: Baicalein inhibited TPC-1 cell viability, migration and invasion, upregulated miR-206 expression, and reduced the RAP1B level in a concentration-dependent manner (p < 0.01). miR-206 negatively regulated RAP1B expression and increased the baicalein-induced reduction of RAP1B expression. Moreover, RAP1B overexpression relieved the suppression of cell viability, migration, and invasion caused by baicalein (p < 0.01).Conclusion: Baicalein suppresses cell growth in PTC cells by regulating the miR-206/RAP1B pathway, providing a new therapeutic strategy for PTC treatment. Keywords: Baicalein, Papillary thyroid cancer (PTC), miR-206, RAP1B, Cell viability, Cell invasion