Laminin: a potential inhibitor of rat glioma cell invasion in vitro.

The lack of metastatic behaviour of primary glioma is poorly understood. A possible natural barrier accounting for this phenomenon may be the proteins of the extracellular matrix which are found in the basement membranes of the blood vascular system. This hypothesis is reinforced by the finding that glioma invasion in vitro using a syngeneic model system results in a lack of invasion of areas of target tissue which contain extracellular matrix proteins. The study was extended by examining the effect of the incorporation of these proteins during the formation of fetal rat brain cell aggregates and glioma spheroids and on the invasion of aggregates by tumour spheroids. Laminin was shown to reduce the size of the aggregates and spheroids during their formation while fibronectin and type IV collagen had no effect. Laminin also prevented the invasion of the tumour spheroid into the target aggregate and appeared to inhibit migration of glioma cells on laminin coated tissue culture plastic.