Expression of multiple integrins and extracellular matrix components by C6 glioma cells.

We have investigated the expression of integrins in C6 glioma, a chemically-induced glial tumor cell line from rat brain. Immunochemical analysis revealed that C6 cells express sets of integrin receptor complexes which immunologically and electrophoretically are indistinguishable from those expressed by normal rat skin fibroblasts. These include the well-characterized fibronectin (alpha 5 beta 1) and the multi-specific laminin, collagen and fibronectin (alpha 3 beta 1) receptors. Assay of cell adhesion indicated that C6 cells adhere to fibronectin-coated surfaces or matrix deposited by the C6 glioma cells (CGM) in an RGD- and divalent cation-dependent fashion. However, anti-fibronectin antibodies, which are able to inhibit fibroblast adhesion to fibronectin, did not inhibit adhesion of the C6 cells to fibronectin or CGM. This may reflect differences in functional properties and/or distribution patterns of integrins in C6 cells and normal fibroblasts.