Long non‐coding RNA AFAP1‐AS1 promoting epithelial‐mesenchymal transition of endometriosis is correlated with transcription factor ZEB1

PROBLEM: The role of the long non-coding RNA (lncRNA) actin filament associated protein 1 antisense RNA1 (AFAP1-AS1) in the etiology of endometriosis is unknown. METHOD OF STUDY: Expression of epithelial-mesenchymal transition (EMT) markers was quantified using qRT-PCR, immunohistochemistry, and Western blotting. The proliferation, migration, and invasion of ectopic endometrial epithelial cells and Ishikawa cells were evaluated by MTT, EdU, wound healing, and transwell assays. Inflammatory cytokine levels were detected by ELISA. Luciferase assays were used to measure activity of the ZEB1 promoter site pGL3-P886. RESULTS: AFAP1-AS1 levels were much higher in ectopic endometrial tissues than that in eutopic tissues. Expression of ZEB1, E-cadherin, and keratin was obviously higher in eutopic tissues than those in ectopic tissues. In contrast, expression of vimentin and N-cadherin was significantly lower in eutopic tissue than those in ectopic tissues. After knockdown of AFAP1-AS1, the morphology of endometrial epithelial cells varied from spindle fiber shaped to polygon epithelioid and proliferation, migration, and invasion were each inhibited. The knockdown of AFAP1-AS1 significantly inhibited expression from promoter site pGL3-P886 of the EMT-related transcription factor ZEB1. The size of subcutaneous tumours in nude mice was significantly reduced after down-regulation of AFAP1-AS1 expression. CONCLUSION: Higher expression of AFAP1-AS1 positively correlated with greater EMT in ectopic endometrium of patients with endometriosis. Knockdown of AFAP1-AS1 inhibited E2-induced activity of promoter site pGL3-P886 of transcription factor ZTB1, suggesting that AFAP1-AS1 knockdown inhibited growth of endometrial epithelial cells and that pathogenesis may be correlated with EMT.