Progesterone receptor expression in meningiomas
The possibility that the female sex steroid progesterone plays a role in meningioma proliferation has been suggested by a number of investigators; and it had been shown that many meningiomas have high affinity progesterone binding sites. The aim of this study was to examine the expression of progesterone receptor mRNA and correlate it with the nuclear localization of progesterone receptor by immunocytochemistry in a large number of meningiomas. Thirty-three meningiomas were examined for the presence of measurable amounts of progesterone receptor mRNA by Northern blot analysis and 11 of these were analyzed for receptor protein by immunohistochemistry. These were compared with normal arachnoid and an arachnoid cell line. Sixty-four % of the meningiomas expressed progesterone receptor mRNA. This occurred in a similar pattern to what has previously been shown for T-47 D cells, a breast carcinoma cell line with 11.4-, 6.1-, 5.2-, 4.5-, 3.2-, and 2.5-kilobase mRNA species. This suggests that progesterone receptor expression is not tumor specific. There was a marked predominance of women among those patients whose tumors expressed progesterone receptor; 81% were female and 19% were male. The immunohistochemistry data correlate well with the Northern blot analysis. The staining was clearly nuclear, suggesting that the receptor is in a location to be activated. These data suggest that progesterone receptor mRNA and protein is expressed in meningiomas and support the concept that progesterone may play an important role in meningioma growth.
Carroll RS, Glowacka D, Dashner KA, Black PM. Progesterone expression in meningiomas . Cancer Research 1993; 53:1312-1316.
Androgen and progesterone receptors in meningiomas
Carroll, RS. Androgen and progesterone receptors in meningiomas-letter . J. Neurosurgery 1993; 79:635-636.
Progesterone and glucocorticoid receptor activation in meningiomas
The possibility that the female sex steroid progesterone plays a role in meningioma proliferation has been suggested by a number of investigators, and it has been shown that many meningiomas have high-affinity progesterone binding sites. There has been a long-standing debate in the literature as to whether the progesterone receptors that are present in meningiomas are functional. We recently showed, by the use of immunohistochemistry, that the progesterone receptor in meningiomas is localized to the nucleus, suggesting that the receptor is in a location to be activated. In this study, eight meningioma cell cultures were transiently transfected with a construct that contains two palindromic progesterone/glucocorticoid response elements in front of the thymidine kinase promoter and the chloramphenicol acetyl sequence of the tyrosine aminotransferase gene. In all meningioma cell cultures, an increase in the transcription of the progesterone response element construct was observed in the presence of dexamethasone, suggesting that the glucocorticoid receptor in meningiomas is functional. An increase in transcription was observed with the addition of promegestone (R5020), a progesterone agonist, only in meningioma cell cultures that were expressing the progesterone receptor. These data show that both the progesterone and the glucocorticoid receptor in meningiomas are functional and support the concept that progestins and glucocorticoids may play an important role in meningioma growth.
Carroll RS, Zhang J, Dashner K, Black PM. Progesterone and glucocorticoid receptor activation in meningiomas . Neurosurgery 1995; 37:92-97.
designed by symposi.com