Growth of a medulloblastoma on normal leptomeningeal cells in culture: interaction of tumor cells and normal cells.

Well-characterized medulloblastoma cells growing in suspension were placed on top of a confluent monolayer of leptomeningeal cells. In contrast to cells placed on plastic alone, which did not grow or attach, the medulloblastoma cells attached readily to the leptomeningeal cells and grew to form enlarging spheroids. The growth of these spheroids was supported with minimal essential medium containing 10% fetal calf serum or with human cerebrospinal fluid. Medulloblastoma cells grown on plastic remained viable for 7 to 10 days, whereas those grown on a monolayer of leptomeningeal cells remained viable for 40 days. Electron microscopy demonstrated increased interdigitation of the plasma membrane at the sites of contact between leptomeningeal and medulloblastoma cells, the deposition of fine, basement membrane-like material between the two cell types, and an increased number of cytoskeletal filaments in the leptomeningeal cells. We conclude that medulloblastoma cells can be grown on a leptomeningeal monolayer. This in vitro system may be useful in studying the mechanisms by which medulloblastoma cells attach to leptomeningeal elements and grow after dissemination in cerebrospinal fluid.