The N-cadherin/catenin complex in colon fibroblasts and myofibroblasts.

Fibroblasts and myofibroblasts were isolated respectively from normal colon mucosa and from colon cancers. Immunostaining with an antibody against alpha-smooth muscle actin (alpha-SMA) of the tissues of origin and of early passage cultures showed equal proportions of alpha-SMA positive myofibroblasts in vivo as in vitro. Immunocytochemistry, immunoprecipitation of metabolically labelled cells followed by Western blotting and RT-PCR of RNA isolates demonstrated the presence of a N-cadherin/catenin complex in both fibroblasts and myofibroblasts. This complex was found preferentially at the cell cell boundaries. Immunocytochemistry and, to a lesser extent, co-immunoprecipitation indicated partial colocalisation of catenins and alpha-SMA. Transforming growth factor beta1 (TGF-beta1) greatly enhanced the expression of alpha-SMA, but left the N-cadherin/catenin complex unaltered. We speculate that the N-cadherin/catenin complex may have different functions in myofibroblasts than in fibroblasts because of its interaction with alpha-SMA.