[Isolation and characteristics of the extracellular matrix of cultured cells]

Sodium deoxycholate extraction was used to isolate extracellular matrix from various cultured cells: human and murine embryonic fibroblasts, epithelial lines of mouse (MPTR), rat (IAR 2 and IAR 20), pig (SPEV) and cow (FBT). Protein composition of the matrix was studied by sodium dodecyl sulfate polyacrylamide gel electrophoresis and immunofluorescence. The matrix morphology was investigated by scanning electron microscopy. In cell lines FBT and MPTR the major component of the matrix was laminin, whereas in other lines and fibroblasts it was fibronectin. The matrix of the majority of lines had a fibrillar structure, and the fibrils usually formed networks. MPTR cells had a punctate matrix composed of laminin and collagen type IV, densely covering the substratum. The treatment of the matrix by hyaluronidase and/or DNAase I did not influence its protein composition. The isolated matrix of different structure and composition may serve a biological substratum in studies of normal tumor cell behavior in tissue culture.