Upregulation of SOX2 activated LncRNA PVT1 expression promotes breast cancer cell growth and invasion

Increasing evidences indicated that Long noncoding RNAs (lncRNAs) played pivotal roles during tumorigenesis in multiple types of cancers, including breast cancer. This study aimed to investigate the role and function of long noncoding RNA PVT1 in the progression of breast cancer and explore the transcription factor which contributes to the regulation of PVT1 in breast cancer. Our results indicated that the expression of PVT1 was significantly upregulated in breast cancer tissues, compared with adjacent normal tissues (ANTs). And the increasing expression of PVT1 was associated with clinical stage, lymph nodes metastasis, and overall survival in breast cancer patients. Using computational screening, a transcriptional factor binding site was found between SOX2 and PVT1 promoter and the interaction between each other was further verified by chromatin immunoprecipitation (ChIP) analysis. In addition, ectopically overexpression of SOX2 can enhance breast cancer cell proliferation and invasion, while knockdown of SOX2 or PVT1 can severely attenuate this effect both in epithelial and mesenchymal types of breast cancer cells. Further evidences confirmed that overexpression of SOX2 can promote breast cancer cell EMT process; while silencing SOX2 or PVT1 expression can undermine this effect. These data suggest that elevated expression of SOX2 can activate lncRNA PVT1 expression promoted breast cancer tumorigenesis and progression. PVT1 may be a prognostic predictive biomarker for breast cancer, and the interaction of PVT1-SOX2 could be a therapeutic target in breast cancer.