OBJECTIVETo 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.

METHODSExpression 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.

RESULTSExpression 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.

CONCLUSIONp120tn 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.

Cadherins ; metabolism ; Carcinoma, Hepatocellular ; metabolism ; pathology ; Catenins ; Cell Adhesion ; Cell Adhesion Molecules ; metabolism ; Cell Line, Tumor ; Cell Membrane ; metabolism ; Cell Movement ; Cell Nucleus ; metabolism ; Cell Proliferation ; Cytoskeletal Proteins ; metabolism ; Cytosol ; metabolism ; Epidermal Growth Factor ; pharmacology ; Humans ; Liver Neoplasms ; metabolism ; pathology ; Phosphoproteins ; metabolism ; Phosphorylation ; Protein Transport ; Trans-Activators ; metabolism ; Tyrosine ; metabolism ; beta Catenin