Distinctive GABA A receptor subunit expression modulates cell specific EMT and functional responses in glioblastoma breast and ovarian cancer

Given the emerging understanding of neurotransmitter involvement in cancer biology, GABA receptors have garnered attention for their diverse and sometimes controversial roles across cancer types. Hence, this study aimed to investigate the expression patterns of GABA-A receptors in glioblastoma, breast, and ovarian cancer cells and their impact on cellular responses via an agonist‒antagonist approach. Cell proliferation and cytotoxicity were assessed using MTT and AO/PI assays, respectively. GABA treatment significantly influenced proliferation, stimulating it in ovarian A2780CP cells overexpressing GABRG3 and inhibiting it in U87 glioblastoma cells, which showed increased expression of GABRR3. Furthermore, GABA reduced CD133+ and CD44+ stem-like populations in A2780CP cells and decreased the CD44+ fraction in MDA-MB231 cells, correlating with specific GABA-A receptor subunit expression. Migration assays revealed that GABA significantly reduced the motility of MDA-MB231 and MCF-7 cells, possibly through modulation of GABRR2 expression. EMT-related transcription factors and markers were evaluated using qPCR, flow cytometry, and Western blot analysis. Protein-level changes in EMT markers confirmed the transcriptional data, with GABA modulating E-cadherin and Vimentin expression in a cell-specific manner. These findings underscore the critical role of GABA-A receptor subtypes in promoting or suppressing cancer progression through context-dependent regulation of proliferation, stemness, migration, and EMT.