Discovery of repurposed ethacrynic acid and its derivatives as novel TEAD inhibitors

The Hippo pathway, a highly conserved growth-inhibitory signaling cascade, critically regulates fundamental processes including development, tissue homeostasis, and tumorigenesis. Its distal effectors, the homologous oncogenic transcriptional coactivators YAP/TAZ, are crucial for cell proliferation, survival, and fate. Frequently upregulated in human cancers, YAP/TAZ drive tumor progression and resistance to chemotherapy/immunotherapy, making them promising therapeutic targets. However, their inherent disordered structures pose challenges for direct targeting. Due to the fact that YAP/TAZ primarily exerts carcinogenic activity by regulating gene expression through binding to TEAD transcription factors, regulating TEADs provides an indirect strategy. Notably, TEADs undergo essential autopalmitoylation, serving as a critical checkpoint that regulates their homeostatic protein levels within cells, while also providing appropriate stability and flexibility for efficient interaction with YAP/TAZ. This post-translational modification can be disrupted by small molecule inhibitors. In this study, a virtual screening of DrugBank database against the TEAD palmitoylation cavity revealed the FDA-approved diuretic drug ethacrynic acid (EA) as a TEAD binder, which was validated by using 1D NMR waterLOGSY, thermal shift assay and isothermal titration calorimetry. Subsequently, we confirmed that EA directly binds to TEAD palmitoylation pocket, inhibiting its palmitoylation, destabilizing TEAD conformation, disrupting YAP-TEAD interaction, and suppressing transcriptional activity. In YAP-activated MDA-MB-231 and NCI-H226 cells, EA downregulates YAP-TEAD target genes (CTGF and CYR61) and inhibits proliferation, colony formation, and migration. These findings establish EA-mediated TEAD suppression as a novel molecular mechanism for its anti-tumor effects. Furthermore, the structure-based optimization of EA yielded novel covalent TEAD inhibitors with enhanced activity. Representative compound EA-C15 covalently binds to the TEAD palmitoylation site, blocks palmitoylation and transcriptional activity, and inhibits NCI-H226 cell proliferation and YAP-TEAD target gene transcription at sub-micromolar concentrations. Collectively, these results establish EA and its derivatives as promising TEAD inhibitors that will provide molecular tools and insights for developing YAP-TEAD-targeted anti-tumor therapies.

Anti-tumor; Covalent inhibitor; Ethacrynic acid; Hippo pathway; YAP-TEAD interaction.