Effects of progesterone on the response to epidermal growth factor and other growth factors in cultured human meningioma cells.

The presence of receptors for progesterone in a large proportion of human meningioma tissues is well established. The occurrence of increased rates of growth of meningiomas in situ during pregnancy suggests the existence of a relationship between high progesterone levels and the growth of meningiomas. However, experiments with cultured meningioma tissue (cells or explants) have shown only minimal effects of progesterone. It has been shown recently that many meningiomas have receptors for epidermal growth factor. In this paper we have investigated the response of cultured human meningioma cells to epidermal growth factor and other growth factors and the modulation of this response by progesterone and the progesterone-receptor blocking agent mifepristone (RU 38486). The results suggest that the presence of progesterone in the culture medium increases the sensitivity of meningioma cells to mitogenic stimuli, whereas mifepristone can counteract the stimulating effects of progesterone.