A coculture assay to visualize and monitor interactions between migrating glioma cells and nerve fibers.

Glioma-cell migration is usually assessed in dissociated cell cultures, spheroid cultures, acute brain slices and intracranial implantation models. However, the interactions between migrating glioma cells and neuronal tracts remain poorly understood. We describe here a protocol for the coculture of glioma cells with myelinated axons in vitro. Unlike other methods, this protocol allows the creation of in vitro conditions that largely mimic the complex in vivo environment. First, long retinal axons from embryonic chicken are formed in an organotypic culture. Glioma cells are then positioned in the vicinity of the explants to allow them to contact the axons, interact with them and eventually migrate along them. High-resolution video microscopy and confocal microscopy can be used to monitor the migratory behavior. This protocol, which takes about 5 days to complete, could be applied to different types of tumor cells that interact with neurites, and is suitable for pharmacological and genetic approaches aimed at elucidating mechanisms underlying tumor migration.