Migration of Human Glioma Cells on Myelin

Histoanatomically invading astrocytoma cells appear to migrate along distinct structures within the brain. Astrocytoma invasion may occur along extracellular matrix (ECM) protein-containing structures, such as blood vessels, but most frequently occurs along tracts of myelinated fibers. This behavior most likely is a consequence of the use of constitutive extracellular ligands expressed along the pathways of preferred dissemination. Enzymatic modification of the extracellular space or deposition of ECM by the tumor cells may also create a more permissive environment. Established human glioma cell lines and two preparations of primary cells isolated from glioblastoma biopsies were studied with the use of cell adhesion and monolayer migration assays to investigate whether crude human central nervous system myelin extracts present specific cell adhesion ligands that promote glioma attachment and cell migration. Two cell lines showed high levels of adhesion and migration on central nervous system myelin similar to levels of migration on the ECM protein merosin, which has previously been shown to be a highly permissive substrate for cultured astrocytoma cells. Two other cell lines showed lower but specific migratory response; one cell line did not attach or specifically migrate on crude myelin extracts. For both glioblastoma primary cell preparations, myelin and merosin were the most permissive substrates for attachment and migration. Other ECM proteins (collagen type IV, fibronectin, and vitronectin) were moderate or nonpermissive substrates. Our findings indicated that astrocytoma cells may be able to use oligodendrocyte membrane-associated ligands as well as ECM proteins of the basement membranes for invasion of normal brain.