lncRNA FENDRR as a Prognostic Biomarker and Regulator of Bladder Cancer Progression via the miR-18a-5p/ESR1 Axis

Recent research highlights the pivotal function of long non-coding RNAs (lncRNAs) in bladder cancer (BCa) progression, emphasizing the need to understand their functions. The clinical significance and molecular mechanisms of lncRNA FENDRR in BCa needed to be elucidated. The Gene Expression Omnibus (GEO) database for BCa-related lncRNAs was screened. Tumor and para cancerous tissues from 118 patients with BCa were collected. Real-time quantitative polymerase chain reaction assessed FENDRR, microRNA (miR)-18a-5p, and estrogen receptor 1 (ESR1) levels. Kaplan-Meier curves assessed FENDRR's prognostic significance. Cell Counting Kit-8, Transwell, and flow cytometry evaluated cell proliferation, migration, invasion, and apoptosis. Dual-Luciferase Reporter and RNA Immunoprecipitation assays revealed miR-18a-5p targeting of FENDRR and ESR1. FENDRR exhibited differential expression in BCa GEO databases. Notably, FENDRR and ESR1 were downregulated, while miR-18a-5p was upregulated in BCa tissues and cell lines. Low FENDRR expression correlated with poor clinical prognosis. Upregulating FENDRR hindered cell proliferation, migration, and invasion while promoting apoptosis; however, miR-18a-5p reversed this suppression. Mechanistically, miR-18a-5p directly targets both FENDRR and ESR1. Our study reveals that low FENDRR expression is a poor prognostic indicator in BCa. FENDRR inhibits miR-18a-5p to upregulate ESR1 and hinder cancer progression, suggesting potential therapeutic targets.