Cadherin Dysfunction in a Human Cancer Cell Line: Possible Involvement of Loss of α-Catenin Expression in Reduced Cell-Cell Adhesiveness¹ Free

A human lung cancer cell line, PC 9, was analyzed to elucidate the molecular mechanisms of dysfunction of cadherin-mediated cell-cell adhesion in cancer. Although PC 9 cells strongly expressed E-cadherin at the cell membrane, which was indistinguishable immunochemically from functional E-cadherin, they did not show tight cell-cell adhesion and had reduced E-cadherin-mediated aggregation activity. Immunoprecipitation with E-cadherin and Western blot analysis revealed that PC 9 cells did not express α-catenin, a cadherin-associated protein, suggesting that this was the cause of the cadherin dysfunction in the cell line. In addition, Northern and Southern blot analyses disclosed homozygous deletion of part of the α-catenin gene, which might have resulted in the loss of α-catenin expression in PC 9 cells.