Abstract A129: Generation of YAP-TEAD Protein-Protein Interaction (PPI) inhibitors for the treatment of cancer

In the last few years the Hippo pathway has been recognized as a critical player in several processes involved in cancer progression, including cell proliferation, apoptosis and EMT. YAP and TAZ mediate the downstream effects of Hippo signaling, and high nuclear expression of YAP has been documented in many tumors including lung, colorectal, ovarian and skin cancers. When YAP translocates to the nucleus it binds to TEAD transcription factor and drives the expression of several growth factors, including CTGF, Cyr61 and survivin. This suggests that therapies targeting YAP-TEAD interaction are likely to have clinical impact for the treatment of cancer patients. However, due to the challenging nature of protein-protein interactions (PPIs), a potent inhibitor that surpasses the affinity of the YAP-TEAD interactions has not been developed. The YAP-TEAD complex has 3 interfaces, and all the critical residues for YAP-TEAD interaction belong to interface S3. In order to identify interface S3-TEAD binders able to disrupt the YAP-TEAD interaction, we started a drug discovery program based on a combined FBLD/HTS strategy. Drugabbility of TEAD protein was assessed by a fragment screen using NMR and SPR technologies. This approach, supported by assigned HSQC protein NMR information, provided fragment hits which were used as starting points for the identification of more potent binders. We also designed a dedicated AlphaScreen assay to validate the ability of our compounds to disrupt the YAP-TEAD interaction. Fifty thousand compounds of Inventiva9s proprietary library were screened using the AlphaScreen assay. Several hits in the μM range were identified and further confirmed using SPR. Successful chemistry optimization based on the critical choice of starting Hit series during the Hit-to-Lead phase led us to generate compounds showing inhibitory activity in the AlphaScreen assay in the range of 50-100 nM for the best compounds. To further confirm the validity of our YAP-TEAD inhibitors, we constructed plasmids encoding TEAD protein fused to the Gal4 DNA-binding domain and transfected HEK293 cells with these plasmids together with a Gal4-driven luciferase reporter plasmid in the presence of YAP S127A. Our compounds showed a marked inhibition in the YAP-TEAD cell-based transactivation assay at concentrations ranging from 3-10 μM. In conclusion, we have successfully demonstrated that YAP-TEAD protein-protein interaction can be inhibited by small molecules, and that our compounds show activity in a cell-based assay. They are currently being evaluated for their ability to block cancer cell proliferation, and SAR on the various series is currently ongoing to improve potency and DMPK parameters for further in vivo evaluation in appropriate cancer xenograft models. Citation Format: Anne Soude, Martine Barth, Stephanie Bocart, Frederic Thoreau, Elina Mandry, Sylvie Contal, Philippe Masson, Isabelle Braccini, Christian Montalbetti, Pierre Broqua, Claudia Z-A Fromond. Generation of YAP-TEAD Protein-Protein Interaction (PPI) inhibitors for the treatment of cancer. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr A129.