Long non-coding RNA TUG1 promotes cell proliferation and metastasis in human breast cancer

Long non-coding RNAs (LncRNAs) utilize a wide variety of mechanisms to regulate RNAs or proteins on the transcriptional or post-transcriptional levels. Accumulating studies have identified numerous LncRNAs to exert critical effects on different physiological processes, genetic disorders, and human diseases. Both clinical tissues from breast cancer patients and cultured cells were used for the qRT-PCR analysis. Specific siRNAs were included to assess the roles of TUG1 with cell viability assay, transwell assay, and cell apoptosis assay, respectively. The expression of TUG1 was enhanced in breast cancerous tissues and in highly invasive breast cancer cell lines and was associated with clinical variables, including tumor size, distant metastasis and TNM staging. Knockdown of TUG1 significantly slowed down cell proliferation, cell migration, and invasion in breast cancer cell lines MDA-MB-231 and MDA-MB-436. In addition, cell apoptotic rate was shown to increase upon siTUG1 treatment as evidenced by increases of the activities of caspase-3 and caspase-9. The identification of TUG1 as a critical mediator of breast cancer progression implied that it might serve as a biomarker for the diagnosis and treatment of breast cancer in clinic.