Different substrates influence the expression of intermediate filaments and the deposition of basement membrane proteins.

A primary culture of serous cystadenocarcinoma of the ovary was used to study the expression of intermediate filament proteins and the deposition of basal lamina proteins. It was found that cells grown on type I and IV collagens or in collagen gels failed to express vimentin, which was readily demonstrable in cultures of the same cells grown on plastic or glass. Furthermore cells grown in collagen gels formed colonies demonstrating a cystic architecture. Unlike what is commonly observed on glass or plastic, where laminin and fibronectin are deposited as disorganized fibrils in the extracellular space, in or on collagen these proteins appear solely at the interface between the epithelial cells and matrix. The results suggest that the extracellular matrix influences the cytoskeletal organization of the intermediate filaments and determines cell polarity. They confirm that collagen substrates permit epithelial cell cultures to progress toward a more differentiated state.