Abstract 2646: Ankrd1 enhances lamellipodia formation and cell motility in clear cell renal cell carcinoma

Abstract Introduction: Clear cell renal cell carcinoma (ccRCC) displays more mesenchymal traits compared to other cancers. These traits include mesenchymal motility, which involves membrane protrusions like lamellipodia formed by actin polymerization. Ankyrin repeat domain 1 (Ankrd1) is regulated by YAP and ERK5, and contains structures that facilitate protein-protein interaction. Ankrd1 has been linked to epithelial-mesenchymal transition (EMT), cancer progression, and drug resistance in various cancers. However, its role in ccRCC remains unexplored. This study investigates Ankrd1 expression, regulation, and function in ccRCC. Methods: We analyzed Ankrd1 expression using the TCGA database and tissue samples via immunohistochemistry. Regulation of Ankrd1 was examined by observing its response to YAP inhibitor and ERK5 inhibitors. Functional studies included siRNA, MTS assay, cell invasion assay, Western blotting, and immunofluorescence imaging. Results: High Ankrd1 expression correlated with poor prognosis of ccRCC patients in TCGA cohort. In tissue samples, metastatic tissues showed higher Ankrd1 levels compared to primary tissues in the same patients. YAP regulated Ankrd1 in all ccRCC cell lines, while ERK5 influenced expression in some ccRCC cell lines. Ankrd1 silencing reduced cell viability under low-density conditions, where YAP activity is prominent. Ankrd1 silencing decreased cell motility, whereas overexpression enhanced motility without altering EMT-related protein levels. Ankrd1 co-localized with F-actin in lamellipodia stimulated by TPA. Ankrd1 silencing altered cell shape and reduced lamellipodia formation. Ankrd1 also interacted and co-located in lamellipodia with Talin-1. Ankrd1 depletion repressed activation of integrin pathway by Talin-1. Conclusion: Ankrd1 is critical for lamellipodia formation and cell motility in ccRCC. Citation Format: Hiromi Ito, Yuki Takai, Sei Naito, Takafumi Narisawa, Norihiko Tsuchiya. Ankrd1 enhances lamellipodia formation and cell motility in clear cell renal cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 2646.