CircATRNL1 increases acid-sensing ion channel 1 to advance epithelial-mesenchymal transition in endometriosis by binding to microRNA-103a-3p.

Circular RNA ATRNL1 (circATRNL1) has been implicated in epithelial-mesenchymal transition (EMT) during endometriosis. Given the existing literature and our predictions through starBase in this research, it was assumed that circATRNL1 might orchestrate the microRNA (miR)- 103a-3p/acid-sensing ion channel 1 (ASIC1) axis to control EMT in endometriosis. To verify our hypothesis, we detect circATRNL1, miR-103a-3p, and ASIC1 expression in endometrial cancer cells (HEC-B, AN3-CA, KLE, HEC1-A, and Ishikawa). Ishikawa cells with the highest circATRNL1 level were selected as subjects, where circATRNL1, miR-103a-3p, or ASIC1 expression was knocked down. Scratch and Transwell assays were applied to assess cell migration and invasion, and CCK-8 and colony formation assays to detect cell proliferation. Western blot was used to measure E-cadherin, N-cadherin, Vimentin, and Slug expression to evaluate the EMT state. Furthermore, the binding of miR-103a-3p to circATRNL1 or ASIC1 was validated by luciferase reporter assay. CircATRNL1 and ASIC1 were upregulated but miR-103a-3p was downregulated in endometrial cancer cells. Mechanistically, circATRNL1 bound to miR-103a-3p to upregulate a target gene of miR-103a-3p, ASIC1. CircATRNL1 silencing contributed to the decline of proliferation, invasion, migration, and EMT in Ishikawa cells, while miR-103a-3p inhibitor reversed those changes. In addition, the EMT process was aggravated when miR-103a-3p was inhibited and this process was suppressed by silencing ASIC1 in the presence of downregulated miR-101a-3p. Our study supported that circATRNL1 might be a novel therapeutic candidate target for endometriosis treatment and provided unique insights into the molecular basis concerning the pathogenesis of endometriosis.