An inhibitor of Wnt/β-catenin signaling; reduces Wnt3a-induced transcriptional activity in a reporter activity assay using STF3a cells, which exhibit constituitive Wnt activation, at 1 µM; inhibits proliferation of, and DNA transcription in, HT-29 cells (IC50s = 9 and 63 nM, respectively) and reduces survival in six other cancer cell lines (IC50s = 14-80 nM); induces cell cycle arrest at the G1 phase in HCT-15 cells at 625 nM; reduces tumor volume and inhibits lung metastasis in a Saos-2 osteosarcoma xenograft mouse model at 50 mg/kg per day