Figure 6

Ncadk.i. alveolar epithelial cells exhibit signs of epithelial-mesenchymal transition (EMT). (A) The ROSA26 reporter allele was used to trace recombined alveolar epithelial cells. LacZ expression, visualized by X-gal staining, indicates Cre activity which normally is restricted to alveolar epithelial cells as shown in the control;p53 sample. Many LacZ-positive epithelial cells in Ncadk.i. and Ncadk.i.;p53 mammary glands changed their cell shape, migrated outside the alveoli, and were found in the stromal compartment. This process was accompanied by the activation of p-Erk and the upregulation of Snail1. Scale bar: 100 μm. (B) Western Blot analysis revealed the upregulation of the mesenchymal marker Vimentin in Ncadk.i. and Ncadk.i.;p53 mammary glands. Notably, Vimentin, but not Snail, is also upregulated in Ecadk.o. and Ecadk.o.;p53. GAPDH was used for the loading control. control;p53, WAP::Cre; Ecad^fl/+; Ncadk.i., WAP::Cre;Ecad^Ncad/fl; GAPDH, Glyceraldehyde 3-phosphate dehydrogenase; Ncadk.i.;p53, WAP::Cre;Ecad^Ncad/fl;p53^fl/+; p-Erk, phospho-extracellular signal-regulated kinase; ROSA26, reverse orientation splice acceptor 26; X-gal, 5-bromo-4-chloro-indolyl-galactopyranoside.