Novel small molecule activators of beta-catenin-mediated signaling pathway: structure-activity relationships of indirubins.

Based on the beta-catenin-drived Wnt activator of bromoindirubin-3'-oxime (BIO), indirubin analogs were evaluated for beta-catenin-mediated gene expression. A novel indirubin analog, indirubin-5-nitro-3'-oxime (INO), was considered a potential activator, and structure-activity studies were conducted with indirubins. These data suggest that INO might be a novel Wnt activator and has a potential of signaling regulator in beta-catenin-mediated signaling pathways.