BIOSYNTHESIS OF BASEMENT-MEMBRANE MOLECULES BY SALIVARY ADENOID CYSTIC CARCINOMA-CELLS - AN IMMUNOFLUORESCENCE AND CONFOCAL MICROSCOPIC STUDY

The biosynthesis of basement membrane molecules and fibronectin was st udied in vitro in the two different human cell systems (ACC2 and ACC3) established from adenoid cystic carcinomas (ACC) of the salivary glan d using immunofluorescence and confocal microscopy. When the cells wer e attached and spread on dishes, fine granular immunofluorescence for type IV collagen, laminin heparan sulphate proteoglycan, entactin, and fibronectin fil st appeared diffusely in the cytoplasm? and then chan ged into aggregation of coarse granules in the perinuclear area. With formation of colonies, these signals were present in the extracellular space, initially in the basal aspect of attached cells and consequent ly in the lateral intercellular space. After the cells formed a conflu ent monolayer, extracellular signals started to decrease in inverse pr oportion to the reappearance of intracellular ones. The results indica te that the parenchymal cells of ACC synthesize these five extracellul ar matrix molecules, secrete them into the extracellular milieu and re model the extracellular deposits. It is suggested that the: characteri stic stromal architecture of ACC, represented by stromal pseudocysts, results from their own secretion of the basement membrane molecules an d fibronectin.