ESRP2 constrains EMT plasticity associated with ZEB1 expression in bladder cancer

Introduction: Epithelial-to-mesenchymal transition (EMT)-driven phenotypic plasticity promotes bladder cancer (BC) progression and therapy resistance. While EMT has been primarily associated with transcriptional reprogramming, the contribution of post-transcriptional mechanisms, particularly alternative splicing regulation, remains insufficiently explored. This study aimed to investigate the clinical significance and mechanistic role of epithelial splicing regulatory protein 2 (ESRP2) in BC. Methods: Integrative analyses of publicly available transcriptomic datasets (TCGA and GEO) were performed to evaluate the prognostic value of ESRP2 and its association with epithelial and mesenchymal phenotypes in BC cell lines. Functional assays, including ESRP2 knockdown and overexpression, were conducted to assess its impact on EMT marker expression, cellular behavior, and stemness-related features such as clonogenicity, spheroid formation, and cell surface marker expression. Results: High ESRP2 expression correlated with improved patient survival and an epithelial-like phenotype in BC models. ESRP2 loss induced mesenchymal marker expression and increased cell motility, whereas ESRP2 overexpression restored epithelial morphology, reduced migration, and suppressed anchorage-independent growth. Flow cytometry revealed no significant changes in CD44 expression but showed a moderate increase in CD133+ cells following ESRP2 overexpression, suggesting a qualitative shift in stem-like subpopulations rather than a global suppression of cancer stemness. Discussion: These findings identify ESRP2 as a key post-transcriptional regulator that constrains EMT-associated transcriptional programs linked to ZEB1 expression, thereby stabilizing epithelial identity in bladder cancer. Targeting alternative splicing may represent a promising therapeutic strategy to limit tumor aggressiveness and overcome treatment resistance.