LncRNA Inhibits the Viability of Triple-Negative Breast Cancer (TNBC) by Targeting the miR-330-5p/BCL2L2 Axis

Long non-coding RNAs (lncRNAs) play important regulatory roles in the progression of kinds of cancers. However, the biological roles of most lncRNAs in breast cancer, especially TNBC, remain unclear. In this study, we investigated the functional of a novel lncRNA, named lncRNA EWSAT1, in the breast cancer and the underlying molecular mechanisms. EWSAT1 was significantly upregulated in the triple negative breast cancer (TNBC) tissues compared with adjacent normal tissues in the GEO databases. We verified the upregulated level of EWSAT1 in the TNBC patients’ serums compared with healthy serums, which also associated with clinical diagnosis. Bioinformatics analysis demonstrated that microRNA (miR)-330-5p was a potential target of SEAS1. Dual luciferase reporter assays confirmed that EWSAT1 functioned as a sponge for miR-330-5p, regulating the expression of BCL2L2. Moreover, RT-qPCR demonstrated that EWSAT1 negatively regulated the expression of miR-330-5p, and positively regulated the expression of BCL2L2 at transcription and protein level. CCK-8 demonstrated that EWSAT1 could inhibit the viability of TNBC cells. In conclusion, our studies find a functional lncRNA EWSAT1 in the TNBC, and reveal a novel pathway for TNBC treatment via EWSAT1/miR-330-5p/BCL2L2, and suggest EWSAT1 might be a potential biomarkers for TNBC diagnosis and therapeutic target for TNBC.