RFX1 and osteosarcoma: We tested 2300 drug-like compounds with activity towards G protein-coupled receptors (GPCR) or kinases for their ability to activate Wnt/β-catenin signaling in a human osteosarcoma U2OS cell line (termed U2OS-EFC) genetically engineered to couple nuclear entry of β-catenin to increases in β-galactosidase complementation [10] and found three hits.