Piezo1 links cytoskeletal remodeling to differential YAP and β-catenin signaling in response to mechanical cues

Mechanical cues from the extracellular matrix regulate cancer cell behavior, but how these inputs are translated into distinct nuclear signaling responses remains incompletely understood. This study examined whether Piezo1, a mechanosensitive ion channel, contributes to cytoskeletal remodeling and differential regulation of YAP and {beta}-catenin localization in breast cancer cells exposed to defined mechanical cues. MDA-MB-231 breast cancer cells were cultured on substrates of defined stiffness and analyzed after Piezo1 knockdown or pharmacological modulation of Piezo1, Src signaling, myosin II activity, and actin polymerization. Nuclear localization of YAP and {beta}-catenin was assessed by immunofluorescence imaging, cytoskeletal organization was evaluated using filamentous and globular actin staining, protein phosphorylation was analyzed by capillary electrophoresis-based immunoblotting, and cell migration was assessed using a wound-healing assay. Piezo1 knockdown reduced YAP nuclear localization and increased {beta}-catenin nuclear localization, while Piezo1 activation partially reversed these localization changes. Piezo1 knockdown also disrupted filamentous actin organization, and pharmacological disruption of actin polymerization produced similar effects on YAP and {beta}-catenin localization. Piezo1 knockdown selectively reduced YAP tyrosine phosphorylation without altering canonical Hippo-associated YAP serine phosphorylation, and inhibition of Src signaling produced effects similar to Piezo1 knockdown. Functionally, Piezo1 knockdown impaired stiffness-dependent cell migration. These findings support a role for Piezo1 in linking extracellular mechanical cues to cytoskeletal organization and differential regulation of YAP and {beta}-catenin localization in breast cancer cells. This work provides a framework for understanding how mechanosensitive ion-channel signaling may contribute to context-dependent nuclear signaling responses during cancer cell mechanotransduction.