Figure 4

Wnt4 does not induce canonical Wnt signaling in mammary epithelial or fibroblast cells in vitro. (A) Wnt reporter assay of primary mammary epithelial cells. Primary mammary epithelial cells were transfected with superTOP-flash reporter gene, a Renilla luciferase gene (a transfection control), and various amounts of Wnt4 expression vector (0.05~2.0 μg). Luciferase activity was measured 48 hrs after transfection, and results corrected for transfection efficiency (dividing by Renilla luciferase activity). Fold induction was calculated with respect to the negative control (LacZ-transfected cells). A Wnt1 expression vector was used as a positive control. (B) Wnt reporter assay of immortalized mammary fibroblast cells. Mammary fibroblast cells were prepared from FVB-Cdkn2a^-/- (Ink4a/Afr null) female mice as described in Materials and Methods, and superTOP-flash reporter assays were performed as above. Error bars = standard deviation of triplicate samples.