Downregulation of the long non-coding RNA ZFAS1 is associated with cell proliferation, migration and invasion in breast cancer.

Long non-coding RNAs (lncRNAs) are non‑coding RNAs that are >200 nucleotides in length. Recent studies have identified a number of lncRNAs with critical roles in various biological processes including tumorigenesis. Zinc finger antisense 1 (ZFAS1) is a lncRNA that has recently been reported to be involved in the progression of several human cancers. However, the biological function of ZFAS1 in breast cancer remains to be elucidated. In order to determine the effect of ZFAS1 in breast cancer cells, reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) was performed to measure ZFAS1 expression in cells from breast cancer cell lines. In addition, gain‑of‑function experiments were performed in vitro to investigate the biological role of ZFAS1. The results revealed that ZFAS1 expression was significantly downregulated in breast cancer cell lines when compared with the levels in controls. In vitro experiments also demonstrated that ZFAS1 overexpression significantly suppressed cell proliferation by causing cell cycle arrest and inducing apoptosis in breast cancer cells. Further functional assays indicated that ZFAS1 overexpression inhibited cell migration and invasion by regulating epithelial‑mesenchymal transition. These findings indicated that the lncRNA ZFAS1 may be a tumor suppressor in breast cancer, and thus, may serve as a potential therapeutic target for patients with breast cancer.