CWP232291, a Wnt/β-catenin inhibitor, to suppress the growth and development of gastrointestinal cancers.

e15534 Background: CWP232291 (JW Pharmaceutical Corp, Seoul, Korea) is a potent β-catenin inhibitor currently tested in phase I trials for AML and MM. We evaluated the preclinical efficacy of CWP232291 for gastrointestinal cancers using xenograft and genetically-engineered mouse (GEM) models. Methods: For xenograft experiments, we intraperitoneally administered 150 mg/kg of CWP232291 twice a week to 14 heterotopic and 2 orthotopic xenografts of human gastric cancer cell lines formed in NOD/SCID mice. For GEM experiments, we intraperitoneally administered 100 mg/kg of CWP232291 (n = 19) or vehicle (n = 27) twice a week for 17 weeks to 3-week-old Villin-Cre;Smad4 F/F ;Trp53 F/F GEM mice that spontaneously form intestinal tumors with the β-catenin signaling activation. Results: CWP232291 exhibited in vivo activity in human gastric cancer xenografts. Activity of CWP232291 was more prominent in human gastric cancer cell lines harboring mutations in the β-catenin signaling pathway, such as APC, and in the 5-FU-resistant derivative of SNU-620, than in the other xenografts (P = 0.028, t-test). In the MKN-45 orthotopic xenograft, we noted a decrease in luciferase signal intensity after 4 weeks of CWP232291 treatment. CWP232291 demonstrated synergistic activity with paclitaxel and irinotecan in the SNU-484 heterotopic xenograft. In GEM experiments, CWP232291 treatment significantly suppressed the spontaneous development of intestinal tumors (56.3% vs. 91.3% with vehicle) in Villin-Cre;Smad4 F/F ;Trp53 F/F mice. Furthermore, CWP232291 treatment significantly reduced the number of mice that develop intestinal adenocarcinomas (37.5% vs. 78.3% with vehicle). Immunohistochemistry revealed CD8 T cell activation within the mouse intestinal tumors. Conclusions: CWP232291 demonstrated significant preclinical efficacy in gastrointestinal tumors, especially in cancers with the β-catenin signaling activation.