Wenzhi Ji

The transcription factor TEAD, together with its coactivator YAP/TAZ, is a key transcriptional modulator of the Hippo pathway. Activation of TEAD transcription by YAP has been implicated in a number of malignancies, and this complex represents a promising target for drug discovery. However, both YAP and its extensive binding interfaces to TEAD have been difficult to address using small molecules, mainly due to a lack of druggable pockets. TEAD is post-translationally modified by palmitoylation that targets a conserved cysteine at a central pocket, which provides an opportunity to develop cysteine-directed covalent small molecules for TEAD inhibition. Here, we employed covalent fragment screening approach followed by structure-based design to develop an irreversible TEAD inhibitor MYF-03–69. Using a range of in vitro and cell-based assays we demonstrated that through a covalent binding with TEAD palmitate pocket, MYF-03–69 disrupts YAP-TEAD association, suppresses TEAD transcriptional activity and inhibits cell growth of Hippo signaling defective malignant pleural mesothelioma (MPM). Further, a cell viability screening with a panel of 903 cancer cell lines indicated a high correlation between TEAD-YAP dependency and the sensitivity to MYF-03–69. Transcription profiling identified the upregulation of proapoptotic BMF gene in cancer cells that are sensitive to TEAD inhibition. Further optimization of MYF-03–69 led to an in vivo compatible compound MYF-03–176, which shows strong antitumor efficacy in MPM mouse xenograft model via oral administration. Taken together, we disclosed a story of the development of covalent TEAD inhibitors and its high therapeutic potential for clinic treatment for the cancers that are driven by TEAD-YAP alteration.

Transcriptional enhanced associate domain (TEAD) proteins together with their transcriptional coactivator yes-associated protein (YAP) and transcriptional coactivator with the PDZ-binding motif (TAZ) are important transcription factors and cofactors that regulate gene expression in the Hippo pathway. In mammals, the TEAD families have four homologues: TEAD1 (TEF-1), TEAD2 (TEF-4), TEAD3 (TEF-5), and TEAD4 (TEF-3). Aberrant expression and hyperactivation of TEAD/YAP signaling have been implicated in a variety of malignancies. Recently, TEADs were recognized as being palmitoylated in cells, and the lipophilic palmitate pocket has been successfully targeted by both covalent and noncovalent ligands. In this report, we present the medicinal chemistry effort to develop MYF-03-176 (compound 22) as a selective, cysteine-covalent TEAD inhibitor. MYF-03-176 (compound 22) significantly inhibits TEAD-regulated gene expression and proliferation of the cell lines with TEAD dependence including those derived from mesothelioma and liposarcoma.

The c-Jun N-terminal kinases (JNKs) are members of the mitogen-activated protein kinase (MAPK) family, which includes JNK1–JNK3. Interestingly, JNK1 and JNK2 show opposing functions, with JNK2 activity favoring cell survival and JNK1 stimulating apoptosis. Isoform-selective small molecule inhibitors of JNK1 or JNK2 would be useful as pharmacological probes but have been difficult to develop due to the similarity of their ATP binding pockets. Here, we describe the discovery of a covalent inhibitor YL5084, the first such inhibitor that displays selectivity for JNK2 over JNK1. We demonstrated that YL5084 forms a covalent bond with Cys116 of JNK2, exhibits a 20-fold higher Kinact/KI compared to that of JNK1, and engages JNK2 in cells. However, YL5084 exhibited JNK2-independent antiproliferative effects in multiple myeloma cells, suggesting the existence of additional targets relevant in this context. Thus, although not fully optimized, YL5084 represents a useful chemical starting point for the future development of JNK2-selective chemical probes.