Figure 2.

sFZD7 inhibits Wnt/β-catenin signaling and suppresses the expression of downstream oncoproteins. (A). sFZD7 decreased nuclear β-catenin accumulation but did not decrease cytoplasmic β-catenin in Huh7 and HepG2 cells. Histone-H3 and β-actin were used as loading controls for nuclear and cytoplasmic proteins, respectively. (B). Tcf4 reporter assay of Tcf4-dependent transcriptional activity in Huh7 and HepG2 cells. Cells were co-transfected with plasmid encoding β-gal (a control for transfection efficiency) and either the pTOPFLASH or pFOPFLASH reporters. Cells were incubated with control PBS or sFZD7 at various concentrations and harvested after 48 h to measure luciferase and β-gal activities. Reporter gene activation is expressed as relative light units (RLU) detected in pTOPFLASH or pFOPFLASH transfected cells and normalized for β-galactosidase activity. The results are expressed as mean ± SD (error bars). Experiments were performed in triplicates (Independent t-test, *P < 0.05.) (C). The effect of sFZD7 on the expression of β-catenin/Tcf4 target genes c-Myc, cyclin D1, and survivin. Huh7 and HepG2 cells were incubated for 48 h with sFZD7 at various concentrations and c-Myc, cyclin D1, survivin, and β-actin (loading control) levels were determined by Western blotting using specific antibodies.