Autocrine control of human meningioma proliferation: secretion of platelet-derived growth-factor-like molecules.

We have used cell-culture techniques to investigate growth-factor production by human meningioma cells. Meningioma tissue was dispersed with collagenase and the cells grown to high density in tissue-culture flasks. The cultures were used to generate conditioned medium (MEN-CM), which was used to cultivate IMR32 cells (a human neuroblastoma line) and freshly dispersed primary meningioma cells. MEN-CM profoundly stimulated the in vitro growth of both IMR32 and meningioma cells. In addition, H3-thymidine uptake by cultured meningioma cells was increased in a dose-dependent manner by varying concentrations of MEN-CM. A neutralizing anti-body against platelet-derived growth factor (PDGF) completely abolished the stimulatory effects of MEN-CM, whereas an antibody against TGF-alpha was without effect. The mitogenic activity of MEN-CM, as assayed by promotion of H3-thymidine uptake by cultured meningioma cells, eluted from a Sephadex G-100 column in 3 peaks corresponding to molecular weights of greater than or equal to 150, 56 and 28 kDa. Our results show that proliferation of human meningiomas may be under autocrine control via secretion of PDGF-like molecules.