Objective  To determine expression of brain-derived neurotrophic factor antisense (BDNF-AS) long non-coding RNA (lncRNA) in breast cancer, and to investigate its effects on proliferation, apoptosis, migration and invasion.

  Methods  Between 2016 and 2018, samples from 88 cases of breast cancer were collected at the First Hospital of Lanzhou University. RT-qPCR was used to determine expression of lncRNA BDNF-AS in breast cancer tissue and cells. A pcDNA3.1 plasmid was used to overexpress BDNF-AS in MDAMB-231 cells. Cell viability was quantified using an MTT assay, proliferative capacity was determined using an EdU assay and a colorimetric assay was used to measure the Caspase-3 activity. Moreover, the protein levels of Bax, Bcl-2, MMP-9, E-cadherin, and BDNF were quantified by Western blot. Scratch and transwell assays were used to determine cell migration and invasion.

  Results  Lower lncRNA BDNF-AS expression was observed in breast cancer tissue and cells compared with normal paracancerous tissues (P < 0.05), and with normal, HBL-100 breast cells (P < 0.01). BDNF-AS expression negatively correlated with tumor-node-metastasis (TNM) stage (P < 0.05) and lymphatic metastasis (P < 0.05) of breast cancer. Overexpression of BDNF-AS with the pcDNA3.1 plasmid decreased viability of MDA-MB-231 cells (P < 0.01), EdU-positive cells (P < 0.01), and Caspase-3 activity (P < 0.01). Additionally, Bcl-2, MMP-9, and BDNF expression was downregulated (P < 0.01), while Bax and E-cadherin expression was upregulated (P < 0.01). Overexpression of BDNF-AS also inhibited cell healing and invasion which were determined by scratch assays (P < 0.01).

  Conclusions  LncRNA BDNF-AS expression is downregulated in breast cancer, which inhibits breast cancer cell proliferation, migration, invasion, and promotes apoptosis.