Inhibition of Wnt activity suppresses supernumerary mammary placode formation in a dose-dependent manner in <i>K14-Eda</i> tissue explants.

(A-E) Stereomicroscope images of E12.5 TOP-gal (A) (n = 17), WT (B, D) and K14-Eda (C, E) explants cultured for 2 days in the presence of 10 μM XAV939 or equal amount of solvent (0.1% DMSO) (B, C), and 40 μM XAV939 or an equal amount of solvent (0.2% DMSO) (A, D, E). Supernumerary placodes were never observed in WT specimen (0/18 explants). (F) Quantification of supernumerary placodes in K14-Eda explants: data are shown as mean ±SD. ***P < 0.001, **P < 0.01. (B, C) WT (n = 10) and K14-Eda (n = 10); (D, E) WT (n = 8) and K14-Eda (n = 8). In all experiments, one side of the embryo was used as the control and the other was treated with XAV939. (Scale bar: 100 μm.)