Discovery of Novel 1-Phenylpiperidine Urea-Containing Derivatives Inhibiting ß-Catenin/BCL9 Interaction and Exerting Antitumor Efficacy through the Activation of Antigen Presentation of cDC1 Cells.

Aberrant activation of the Wnt/ß-catenin signaling is associated with tumor development, and blocking ß-catenin/BCL9 is a novel strategy for oncogenic Wnt/ß-catenin signaling. Herein, we presented two novel ß-catenin variations and exposed conformational dynamics in several ß-catenin crystal structures at the BCL9 binding site. Furthermore, we identified a class of novel urea-containing compounds targeting ß-catenin/BCL9 interaction. Notably, the binding modalities of inhibitors were greatly affected by the conformational dynamics of ß-catenin. Among them, 28 had a strong affinity for ß-catenin (Kd = 82 nM), the most potent inhibitor reported. In addition, 13 and 35 not only activate T cells but also promote the antigen presentation of cDC1, showing robust antitumor efficacy in the CT26 model. Collectively, our study demonstrated a series of potent small-molecule inhibitors targeting ß-catenin/BCL9, which can enhance antigen presentation and activate cDC1 cells, delivering a potential strategy for boosting innate and adaptive immunity to overcome immunotherapy resistance.