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.

Design, synthesis, and biological evaluation of novel 8-substituted quercetin derivatives targeting the ß­catenin/B-cell lymphoma 9 interaction.

The ß-catenin/B-cell lymphoma 9 (BCL9) protein-protein interaction (PPI) is a potential target for aberrantly active Wnt/ß-catenin signaling which actively participates in initiating and progressing of many cancers. Herein, we discovered novel 8-substituted quercetin derivatives with potential inhibitory activities targeting ß-catenin/BCL9 PPI. Among all the derivatives, compound B4 displayed the most promising PPI inhibitory activity with an IC50 value of 2.25 µM in a competitive fluorescence polarization assay and a KD value of 1.44 µM for the ß-catenin protein. Furthermore, B4 selectively inhibited the growth of colorectal cancer (CRC) cells, suppressed the transactivation of Wnt signaling, and downregulated the expression of oncogenic Wnt target gene. Especially, B4 showed potent anti-CRC activity in vivo with the tumor growth inhibition (TGI) of 75.99 % and regulated the tumor immune microenvironment.