LAMININ PROMOTES DIFFERENTIATION, ADHESION AND PROLIFERATION OF CELL-CULTURES DERIVED FROM HUMAN ACOUSTIC NERVE SCHWANNOMA

The influence of laminin on cell cultures derived from unilateral acou stic nerve schwannomas was investigated. Cell cultures were initiated from 12 schwannomas, removed via the enlarged middle cranial fossa app roach. Tumor tissue was dispersed by collagenase treatment and cells s eeded in uncoated or laminin-coated culture dishes. Confluent cultures were immunocytochemically characterized with antibodies against S-100 , CD 68, factor VIII-related antigen and type IV collagen. Cell adhesi on in response to different doses of laminin was evaluated with an ele ctronic cell counter. The effect of laminin on cell proliferation was assessed by measuring the incorporation of 5-bromo-2'-deoxy-uridine (B RDU) into cellular DNA. Cells cultured on laminin as substrate appeare d more differentiated with long, fusiform, cytoplasmic processes. Cult ured cells stained positive for S-100, not for factor VIII-related ant igen or CD 68. Only cells cultured on laminin deposited a dense extrac ellular network of type TV collagen. When laminin was added to the cul ture medium, cell attachment and proliferation was stimulated in a dos e dependent manner. Maximal stimulation of both was observed with a la minin concentration of 50 mu g/ml, which induced a nearly 2-fold incre ase in cell attachment and an approximately 66% increase in DNA conten t. Since laminin is a major component of the extracellular matrix in s chwannomas, the possibility exists that laminin is also mitogenic for human neoplastic Schwann cells in situ.