Objective: To investigate the effect of catenin p120 (p120ctn) translocation on the malignant features of hepatocellular carcinoma and its interrelation with beta-catenin in E-cadherin-mediated cell signaling.
Methods: Expression and translocation of p120ctn, tyrosine phosphorylation, and its binding capacity to E-cadherin were detected by DNA transfection, immunoblotting and immunoprecipitation. Cellular localization of p120ctn and beta-catenin was detected by immunofluorescent microscopy. Cell adhesion, cell migration and cell proliferation were also studied.
Results: Expression of p120ctn increased after cells transfected with p120ctn isoform 3A, and it was located mainly at cell-cell contact region. Its binding to E-cadherin was enhanced. After EGF stimulation, tyrosine phosphorylation of p120ctn was increased, membrane expression of p120ctn and beta-catenin was decreased while cytosol expression was increased. It was translocated into the nucleus, cell adhesiveness was increased but mobility decreased. With over-expression of p120ctn, beta-catenin was recruited by nucleus export. Cell proliferation was reduced but it was increased after EGF treatment.
Conclusion: p120tn plays an important role in cell adhesion, migration and proliferation of hepatocellular carcinoma, and its tyrosine phosphorylation might contribute to this mechanism. There might be a competitive relationship between p120ctn and beta-catenin.