RU486 Blocks the Progesterone-induced Suppression of COX-2 mRNA in T47D Cells. T47D cells were incubated for 6 h the absence or presence of RU486 (10-7M) with and without IL-1β (10 ng/ml), progesterone (10-7 M), or both. RNA was isolated and the expression of COX-2 was analyzed by Q-RT-PCR. The data are expressed as fold increase over vehicle control cells. The bars represent the mean ± S.E.M. of values from three independent experiments. From D.B. Hardy, B.A. Janowski, D.R. Corey, C.R. Mendelson. Progesterone receptor (PR) plays a major anti-inflammatory role in human myometrial cells by antagonism of NF-κB activation of cyclooxygenase 2 (COX-2) expression. Mol. Endocrinol. (2006), in press [72], with permission. Copyright 2006, The Endocrine Society.