Expression and Biological Functions of L1 Cell Adhesion Molecule in Malignant Glioma Cells

Human and rat glioma cells were screened for their expression of the L cell adhesion molecule (L1 CAM) gene and protein by reverse transcriptase-polymerase chain reaction (RT-PCR) and immunodot analysis, respectively. All glioma cells tested expressed the L1 gene in various degrees. They also produced L1 molecules to a certain extent, while normal rat glia did not produce L1. The amount of expression of the L1 gene was related to the cell morphology and cell-cell aggregation patterns in a monolayer cell culture. That is, the more glioma cells expressed the L1 gene, the less polarity they had in cell shape and the more compactly they aggregated when growing in the early phase of cell culture. The glioma cells strongly migrated not only to a synthetic L1 polypeptide but also to L1- or L1 cs-transfected fibroblast cells. These results suggest that L1 expressed in glioma cells may play an important role in the migration of the glioma cells through homophilic or heterophilic cell adhesion, thus participating in tumor invasion, particularly along the nerve fibers.