Significance of epithelial growth factor in the epithelial–mesenchymal transition of human gallbladder cancer cells

Five gallbladder cancer (GBC) cell lines were examined for morphological changes in collagen gel culture. GBh3 and HUCCT‐1 cells formed tubules in response to treatment with epithelial growth factor (EGF) and hepatocyte growth factor (HGF), and showed high levels of expression of E‐cadherin (ECD), and low levels of SNAIL, vimentin, transforming growth factor (TGF)‐β, and nucleostemin (NS). In contrast, the GBd15 and FU‐GBC‐1 cell lines treated with EGF and HGF showed a scattering phenotype, and expressed low levels of ECD and high levels of SNAIL, vimentin, TGF‐β, and NS. All cell lines expressed the EGF receptor, c‐Met, EGF, and TGF‐α, but not HGF. Transforming growth factor‐β was upregulated by EGF. Knockdown of the EGF receptor abrogated both tubule formation and scattering, whereas KD of TGF‐β abrogated only scattering. Knockdown of EGF induced nuclear translocation of β‐catenin and Wnt‐related NS induction in the scattering cell lines, but not in the tubule‐forming cell lines, whereas KD of glycogen synthase kinase‐3β in the tubule‐forming cell lines resulted in the nuclear translocation of β‐catenin and Wnt‐related NS induction in response to EGF treatment. These results suggest that EGF enhances epithelial–mesenchymal transformation and acquisition of stemness in GBC cells with a scattering phenotype through the activity of β‐catenin. Repression of ECD in scattering GBC cells induced the release of β‐catenin from the cell adhesion complexes along the plasma membrane and its translocation to the nucleus to activate Wnt signaling, which upregulated NS. (Cancer Sci 2012; 103: 1165–1171)