Abstract 68: YAP-TEAD-dependent VASP expression increases cell stiffness and migration in TNBC cells under high extracellular glucose conditions.

Abstract Triple negative breast cancer (TNBC) is an aggressive subtype lacking targeted therapies, highlighting the urgent need for novel treatment strategies. Clinical observations indicate that TNBC patients with obesity or diabetes have a worse prognosis, underscoring the impact of metabolic dysregulation on disease progression. We previously demonstrated that extracellular glucose regulates F-actin assembly and non-muscle myosin activity via the cAMP-RhoA-ROCK pathway in TNBC cells, linking glucose metabolism to cytoskeletal remodeling and cell invasion. In this study, we aimed to further elucidate the molecular mechanisms by which extracellular glucose regulates cell mechanics and motility. We hypothesized that the Hippo pathway, particularly YAP, regulates expression of a cytoskeletal remodeling gene, VASP in response to glucose metabolic signaling. To test the hypothesis, we utilized public ChIP-seq datasets, to identify four YAP-TEAD binding domains (CBDs) within the human VASP gene enhancer region. TEAD motif analysis using FIMO revealed predicted TEAD-binding sites in each region. We then experimentally validated those identified CBDs. These enhancer fragments were subcloned into luciferase reporters. For exogenous validation, we measured luciferase activity after TEAD inhibitor treatment and performed site-directed mutagenesis to determine whether TEAD binding is required for VASP gene regulation. To determine which TEAD isoforms contribute most to VASP regulation, we performed siRNA-mediated knockdown of TEAD1-4 and found that TEAD1 and TEAD4 were the most significant regulators of VASP expression. For endogenous validation, we conducted Western Blotting after 24hours of TEAD inhibitor treatment. To test whether this regulatory axis is responsive to glucose levels, we performed glucose-dependent luciferase assays for exogenous validation, and RNA sequencing and Western Blotting to evaluate endogenous VASP expression under different glucose conditions. These analyses demonstrated that the YAP-TEAD-VASP axis is upregulated in high-glucose settings. Finally, to explore the translational implications of these findings, we assessed whether TEAD inhibitors could suppress migration in a hyperglycemic context. Since VASP promotes F-actin polymerization, we hypothesized that TEAD inhibition would reduce F-actin rearrangement and thereby decrease cell contracility, which in turn suppress cell migration. In scratch wound healing assays, TEAD inhibitors significantly reduced cell migration across glucose concentrations tested. In summary, we identify VASP as a novel YAP-TEAD target gene regulated under hyperglycemic conditions and demonstrate that TEAD inhibition alters contracility and suppresses migration in TNBC cells. Citation Format: Wonkyung Lee, Seeun Oh, Tae-Hyung Kim. YAP-TEAD-dependent VASP expression increases cell stiffness and migration in TNBC cells under high extracellular glucose conditions 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 68.