MIR503HG silencing promotes endometrial stromal cell progression and metastasis and suppresses apoptosis in adenomyosis by activating the Wnt/β‑catenin pathway via targeting miR‑191.

MIR503HG is a 786 bp long lncRNA located on chromosome Xq26.3, and it can regulate diverse cellular processes. The pathogenesis of adenomyosis (AD) is associated with endometrial stromal cells (ESCs). The present study investigated the specific role of MIR503HG in AD pathogenesis and progression using ESCs derived from the endometrium of patients with AD as a model. Expression of MIR503HG and microRNA (miR)-191 were assessed using reverse transcription-quantitative PCR. An immunocytochemistry assay was used to detect cytokeratin- or vimentin-positive ESCs. Transfections of ESCs with MIR503HG overexpression plasmid, short hairpin-MIR503HG and miR-191 inhibitor were performed. ESC viability, migration, invasion and apoptosis were evaluated using Cell Counting Kit-8, Transwell and flow cytometry assays. The association between MIR503HG and miR-191 was predicted by StarBase and confirmed using a dual-luciferase reporter assay. Expression of epithelial-mesenchymal transition-related markers (E-cadherin and N-cadherin) and Wnt/β-catenin pathway-related molecules (β-catenin) in ESCs were analyzed by western blotting. The isolated ESCs were vimentin-positive and cytokeratin-negative. MIR503HG was lowly expressed in the endometrial tissues derived from patients with AD. MIR503HG overexpression hindered ESC viability, migration and invasion while enhancing the apoptosis and downregulating miR-191 expression. MIR503HG knockdown induced the opposite effects, accompanied by downregulation of the E-cadherin expression and upregulation of N-cadherin and β-catenin levels. MIR503HG directly targeted miR-191 that was highly expressed in endometrial tissues derived from patients with AD. In ESCs, downregulation of miR-191 inhibited the viability, migration and invasion and the expression of N-cadherin and β-catenin levels while enhancing the apoptosis and E-cadherin expression in ESCs. Moreover, downregulation of miR-191 partially reversed the effect of MIR503HG knockdown. Collectively, overexpressed MIR503HG impeded the proliferation and migration of ESCs derived from endometrium of patients with AD, while promoting apoptosis via inhibition of the Wnt/β-catenin pathway via targeting miR-191.