Long non-coding RNA LINC00665 promotes metastasis of breast cancer cells by triggering EMT.

OBJECTIVE: In recent years, studies have found that abnormally expressed long non-coding RNA (lncRNA) is closely associated with the progression of breast cancer (BCa). Some lncRNAs have been identified to be involved in the regulation of BCa cell invasion and metastasis. In this research, LINC00665 was found to be abnormally expressed in BCa tissues and cells, and its regulatory effects on invasion and metastasis of BCa were explored. The aim of this study was to investigate the expression characteristics of LINC00665 in BCa, and its regulatory role in BCa progression. PATIENTS AND METHODS: LINC00665 expressions in BCa tissue samples and normal ones were collected from GEPIA database. The expression of LINC00665 in BCa tissues and cell lines was further confirmed by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). After knockdown of LINC00665 expression in BCa cells by transfection of small interfering RNA, cell migration and invasion abilities were examined by cell wound healing and transwell assay. Expressions of epithelial-mesenchymal transition (EMT)-related markers in BCa cells were examined using qRT-PCR and Western blot. RESULTS: LINC00665 was highly expressed in BCa tissues and cell lines, and the high expression of LINC00665 could be used to predict a poor prognosis of BCa patients. In addition, the results of in vitro cell experiments showed that the migration and invasion ability of BCa cells were remarkably attenuated after downregulation of LINC00665. At the same time, qRT-PCR and Western blot results revealed that downregulation of LINC00665 was able to inhibit the expressions of EMT-related genes in BCa cells. CONCLUSIONS: LINC00665 is highly expressed in BCa tissues and cell lines, which could predict poor prognosis of BCa patients. In addition, LINC00665 may promote the malignant metastasis of BCa cells by affecting the EMT process.