LncRNA Taurine-Upregulated Gene 1 Promotes Cell Proliferation by Inhibiting MicroRNA-9 in MCF-7 Cells.

Purpose: This study was designed to investigate the role of taurine-upregulated gene 1 () in MCF-7 breast cancer cells and the molecular mechanism involved in the regulation of microRNA-9 (miR-9).

Methods: The expression of in breast cancer tissues and cells was evaluated using quantitative reverse transcription polymerase chain reaction. Cell viability was examined using a 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay; cell cycle progression and apoptosis were analyzed using flow cytometry. A dual luciferase reporter assay was used to detect the relationship between and miR-9. The expression of methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) was measured by western blot.

Results: Higher expression of was observed in breast cancer tissues and cell lines than in the corresponding controls. knockdown reduced proliferation, suppressed cell cycle progression, and promoted apoptosis of MCF-7 cells. The dual luciferase reporter assay showed that could negatively regulate the expression of miR-9. MiR-9 inhibition abrogated the effect of knockdown on the proliferation, cell cycle progression, and apoptosis of MCF-7 cells. positively regulated the expression of MTHFD2 in breast cancer cells.

Conclusion: knockdown was significantly associated with decreased cell proliferation and it promoted apoptosis of breast cancer cells through the regulation of miR-9.