Long noncoding RNA ATB promotes ovarian cancer tumorigenesis by mediating histone H3 lysine 27 trimethylation through binding to EZH2.

Ovarian cancer (OC) remains one of the most lethal gynecological malignancies. The unfavourable prognosis is mainly due to the lack of early-stage diagnosis, drug resistance and recurrence. Therefore, it needs to investigate the mechanism of OC tumorigenesis and identify effective biomarkers for the clinical diagnosis. It is reported that long noncoding RNAs (lncRNAs) play important roles during the tumorigenesis of OC. Therefore, the present study aimed to study the role and clinical significance of LncRNAs ATB (lnc-ATB) in the development and progression of OC. In our research, lnc-ATB expression in OC tissues was elevated compared with adjacent normal tissues and high expression of lnc-ATB was associated with poor outcomes of OC patients. The silencing of lnc-ATB blocked cell proliferation, invasion and migration in SKOV3 and A2780 cells. RNA immunoprecipitation and RNA pull-down results showed that lnc-ATB positively regulated the expression of EZH2 via directly interacting with EZH2. Besides, the overexpression of EZH2 partly rescued lnc-ATB silencing-inducing inhibition of cell proliferation, invasion and migration. Chromatin immunoprecipitation assay results demonstrated that the silencing of lnc-ATB reduced the occupancy of caudal-related homeobox protein 1, Forkhead box C1, Large tumour suppressor kinase 2, cadherin-1 and disabled homolog 2 interacting protein promoters on EZH2 and H3K27me3. These data revealed the oncogenic of lnc-ATB and provided a novel biomarker for OC diagnosis. Furthermore, these findings indicated the mechanism of lnc-ATB functioning in the progression of OC, which provided a new target for OC therapy.