A HETEROLOGOUS IN-VITRO COCULTURE SYSTEM TO STUDY INTERACTION BETWEENHUMAN BLADDER-CANCER CELLS AND FIBROBLASTS

Three-dimensional multicellular spheroids of two fibroblast cell lines (WI-38 and N1) and two differently differentiated bladder carcinoma c ell lines (RT4 and J82) were used for cocultures of multicellular tumo r spheroids with multicellular spheroids of fibroblasts. The aim of th e study was the establishment and characterization of a standardized t hree-dimensional model for studies of tumor cell-fibroblast interactio n as one aspect of tumor-stromal cell interactions of in vivo tumor ti ssue. Interaction of multicellular spheroids of both fibroblast cell t ypes was analyzed by staining with antibodies against cytokeratin, vim entin and different extracellular matrix molecules. Further, prolifera tion assessment and phenotypic characterization of the cocultures are presented. Interactions varied with tumor cell type and fibroblast cel l type, reflecting intrinsic properties of tumor cells and fibroblasts . The coculture of tumor cells with N1 reflected the in vivo situation the closest, since invasive properties of J82 as well as noninvasive properties of RT4 were characteristics seen in coculture.