Figure 5.

Increase in beta-catenin expression during E2 treatment does not result in beta-catenin signaling through TCF/LEF response elements in ROS-PG13 cells. Cells were transfected with TopFlash (wild type promoter) and FopFlash (mutant promoter) luciferase reporters in 2% media, and E2 treatment was started three hours later. E2 treatments were staggered during the 48 h interval and all cells were harvested after 48 h after the indicated time of exposure to the hormone. Mutant FopFlash activity was unchanged during the treatment and is not shown. LiCl treatment was carried out to demonstrate the validity of the assay (Inset). Cells were exposed to LiCl or NaCl 24 h after transfection for 16 h. In both these experiments luciferase activity was measured in cell lysates using equal amounts of protein. Experiments represent average ± SEM of triplicate measurements.