[Structure and function of extracellular matrix with special references to proteoglycan].

To clarify the physiological significance of extracellular matrix components, biochemical and histochemical characterization of glycosaminoglycan and proteoglycan was performed. The glycosaminoglycan, chondroitin sulfate, was favorable to the growth of Ehrlich ascite tumor cells inoculated into the subcutaneous space of the mouse's back. The glycosaminoglycan content and its synthesis by gastric carcinoma tissue were compared with those of non-neoplastic mucosa, after incubation of tissue segments in medium containing 35SO4. The rate of glycosaminoglycan synthesis by medullary carcinoma tissue was much higher than that by the non-neoplastic mucosa, although no significant difference was found in the amount of glycosaminoglycan between them. Using human gastric carcinoma cell lines, the interaction of fibroblasts (cell line WI-38) with carcinoma cells was studied in vitro. In well-differentiated adenocarcinoma, the amount of glycosaminoglycan secreted into the interface between carcinoma cells and fibroblasts was much larger (about 20-fold) than that into the interface between the carcinoma cells and the bare culture dish. However, in poorly differentiated adenocarcinoma cells, glycosaminoglycan secretion was not affected by the presence of fibroblasts. The effects of the extracellular matrix produced by carcinoma cells on the attachment and growth of fibroblasts were also examined in vitro. The attachment-promoting and growth-promoting activities of the matrix substance produced by poorly differentiated carcinoma was about 10 times greater than that caused by the well-differentiated adenocarcinoma cell matrix substance. Proteoglycan and glycosaminoglycan were identified in malignant and benign non-epithelial tumors. More proteoglycans containing mainly chondroitin sulfate could be detected in malignant tumors than in benign tumors.(ABSTRACT TRUNCATED AT 250 WORDS)