Abstract 3474: Effect of Piezo1 activation and CYRI-B loss in melanoma cell membrane dynamics

Abstract Background: Cancer cell migration is a critical step in metastasis, driven by cytoskeletal remodelling in response to extracellular mechanical cues. Piezo1, a mechanosensitive ion channel, has been known to promote cell motility through calcium-dependent activation of actin-regulatory pathways. In parallel, CYRI-B acts as a local inhibitor of lamellipodial protrusion by binding Rac1 to prevent activation of the Scar/WAVE complex. However, whether these two pathways interact to regulate cancer cell motility remains unexplored. Methods: Using B16F1 mouse melanoma cells, we investigated how Piezo1 activation (via the small molecule agonist Yoda1) and CYRI-B knockout influence collective cell migration and membrane fluctuations during cell spreading. Scratch-wound healing assays quantified collective migration, and phase-contract live-cell imaging with kymograph analysis assessed spreading and protrusion behaviour in both wild-type and CYRI-B knockout cells with and without treatment with Yoda1. Results: Piezo1 activation significantly increased collective cell migration by approximately 35%, cell area by approximately 30%, and membrane fluctuations by approximately two-fold in wild-type cells. However, none of these changes were observed after Piezo1 activation in CYRI-B knockout cells. Kymograph analysis showed that protrusion length increased along with protrusion angle after Piezo1 activation in the presence of CYRI-B. However, these increases were also not observed in CYRI-B knockout cells. Conclusion: Our findings show that CYRI-B may influence the Piezo1-mediated increase in cancer cell migration and membrane dynamics. This raises the possibility of a previously unrecognized connection between mechanosensitive Piezo1 activation and CYRI-B-mediated membrane fluctuations, adding a new dimension to membrane dynamics in cancer cell motility and spreading. Citation Format: Advait Raja, Sayantika Ghosh, Laura Machesky. Effect of Piezo1 activation and CYRI-B loss in melanoma cell membrane dynamics abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 3474.