Abstract: Objective To investigate the effects of long noncoding RNA(lncRNA) SLC26A4 antisense RNA 1(SLC26A4-AS1) on proliferation,migration and invasion of breast cancer cell and the underlying mechanisms. Methods From June 2017 to December 2020, there were 40 cases of breast cancer tissue and corresponding paracancer tissue (more than 5cm away from the margin of cancer tissue).The expression levels of SLC26A4-AS1 in breast cancer tissues and cell lines were determined by quantitative real-time PCR(qRT-PCR).MCF7 cell was selected and allocated into:control group,pcDNA3.1 group,pcDNA3.1-SLC26A4-AS1 group and pcDNA3.1-SLC26A4-AS1+Notch activator group.The effects of SLC26A4-AS1 on expressions of Notch1 and Hes1 in Notch signaling pathway were examined by qRT-PCR.Cell viability(Proliferation),migration and invasive were determined by MTT assay,Scratch and Transwell assay. Results SLC26A4-AS1 was significantly down-regulated in breast cancer tissues and cell lines.The expressions of Notch1 and Hes1 in pcDNA3.1-SLC26A4-AS1 group were lower than pcDNA3.1 group(P<0.01).The cell viability,wound healing rate and number of transmembrane cells of pcDNA3.1-SLC26A4-AS1 group were inhibited compared with pcDNA3.1 group(P<0.01).The cell viability,wound healing rate and number of transmembrane cells of pcDNA3.1-SLC26A4-AS1+Notch activator group were promoted compared with pcDNA3.1-SLC26A4-AS1 group(P<0.01). Conclusions SLC26A4-AS1 was down-regulated in breast cancer,and overexpression of SLC26A4-AS1 curtailed proliferation,migration and invasion of breast cancer cells.SLC26A4-AS1 provides a novel epigenetic mechanism involved in deactivation of Notch signaling pathway.

Key words: breast cancer, SLC26A4-AS1, Notch1, Hes1