Fig. 4

Cell cycle of T47D cells and BT474 cells after treatment with R5020 [10nM] or E2 [1nM] + R5020 [10nM] alone or in presence of TPA [1 μM]. a. T47D and b. BT474 cells were serum-starved for 24 h and subsequently treated with E2, R5020 and the antiprogestin TPA in various combination as indicated in figure for 24 h. Cell cycle analysis was performed in presence of Propidium Iodide to measure G1, S and G2/M fractions. c. Immunoblot of increased PR expression after 72 h of exposure of BT474 cells to E2 (left) and after 24 h of exposure to R5020 (right). E2 significantly increase both PR-A and B protein expression. The loss of PR expression with exposure to R5020 is indicative of high transcriptional activity and rapid protein turnover [44]. The blot has been cropped to remove the 48 h data. d. *BT474 cells were stimulated with E2 [1nM] for 72 h prior to treatment of R5020 and TPA to increase PR expression