lncRNA NBAT1 Inhibits Cell Metastasis and Promotes Apoptosis in Endometrial Cancer by Sponging miR-21-5p to Regulate PTEN

OBJECTIVE: Long noncoding RNA neuroblastoma-associated transcript 1 (NBAT1) is implicated in the progression of various cancers. Nevertheless, its biological function in endometrial cancer (EC) remains unknown. METHODS: The levels of NBAT1, miR-21-5p, and PTEN in EC cells and EC tissues were examined by RT-qPCR. Western blot was carried out to assess the protein expression of PTEN. The dual-luciferase reporter assay was conducted to explore the interactions among NBAT1, miR-21-5p, and PTEN. The effect of NBAT1 on EC proliferation, metastasis, and apoptosis was evaluated by CCK-8, transwell assays, wound healing, and flow cytometry. miR-21-5p mimics or NBAT1+miR-21-5p were transfected into HEC-1A and Ishikawa cells to investigate whether NBAT1 regulated EC tumorigenesis via sponging miR-21-5p. RESULTS: NBAT1 is downregulated, and miR-21-5p is upregulated in EC cells and tumor tissues. Overexpression of NBAT1 inhibits the proliferation, migration, and invasion abilities of EC cells and facilitated apoptosis. NBAT1 directly binds and negatively regulates miR-21-5p in EC. miR-21-5p mimics reverses the effect of lncRNA NBAT1 overexpression on the proliferation and migration of EC cells. PTEN is a downstream gene of miR-21-5p. lncRNA NBTA1 elevates PTEN expression via sponging miR-21-5p. CONCLUSIONS: lncRNA NBAT1 acts as a tumor suppressor in EC via regulating PTEN through sponging miR-21-5p.