Figure 8

Frequent constitutive activation of canonical Wnt signaling in well-differentiated, but not in poorly differentiated hepatocellular carcinoma cell lines. (a) Comparative analysis of the canonical Wnt signaling in hepatoma cell lines with known mutations of β-catenin or Axin-1 genes. TCF reporter assay shows that well-differentiated HepG2 cells display high signaling activity. In contrast, canonical Wnt signaling is attenuated in poorly differentiated SNU398, and undetectable in poorly differentiated SNU475 cell line. Assays in triplicate, error bars; SD. (b) Comparative analysis of the canonical Wnt signaling in HCC cell lines with wild-type β-catenin and Axin-1 genes. Huh7 and Hep3B cell lines (both well-differentiated) display weak but significantly increased TCF reporter activity. Other cell lines (all poorly differentiated, except Hep40) display no detectable TCF reporter activity. TCF activity denotes the ratio of signals detected with pGL3-OT (OT) and pGL3-OF (OF) plasmids, respectively. Assays in triplicate, error bars; S. D. Cells were transfected with the reporter gene pGL3-OT (OT) harboring LEF-1/TCF binding sites for β-catenin and the corresponding pGL3-OF (OF) without these sites.