Changes in cadherin‐catenin complexes in the progression of human bladder carcinoma

We are investigating the hypothesis that cancer progression involves the formation of abnormal cadherin‐catenin complexes. The detailed analysis of cadherins and catenins expressed in a panel of 17 human bladder‐cancer cell lines revealed that E‐cadherin was down‐regulated at the mRNA level in 5 cell lines. Interestingly, plakoglobin was also down‐regulated at the mRNA level in these 5 cell lines only. Furthermore, a slower migrating form of pp120 was detected in these cell lines and in 2 cell lines with heterogeneous E‐cadherin expression. Cloning of the cadherins expressed in the bladder lines revealed that P‐cadherin is expressed in the lines expressing E‐cadherin and down‐regulated at the mRNA level in lines devoid of E‐cadherin. N‐cadherin was expressed in the 5 lines with reduced E‐cadherin expression, in the 2 lines with heterogeneous E‐cadherin expression and in 2 other cell lines. Thus, we showed that catenin changes occur in correlation with lack of E‐cadherin expression and that N‐cadherin becomes predominantly expressed in cells that have lost E‐cadherin expression. Our data suggest that co‐regulation of the expression of genes encoding different members of the classical cadherins occurs during tumor progression and that expression of some catenins is also coordinated with cadherin expression. Int. J. Cancer 82:70–76, 1999. © 1999 Wiley‐Liss, Inc.