GR activates the
promoter region between -375 and -225 bp only in the absence of HC. A. Schematic of Ch25h promoter fragments cloned into the pRL-Null vector upstream of the Renilla luciferase (R-luc) gene. B-C. EPH-4 cells were transiently transfected with the Ch25h promoter reporters Ch25h-9-pRL, Ch25h-10-pRL, Ch25h-11-pRL Ch25h-11.5-pRL Ch25h-12-pRL, and the L6-pRL BRCA1 promoter reporter, as well as empty vector (EV) or wild-type GR (GRwt) expression vector. Cells were treated 24 hours after transfection with either B. ethanol vehicle (-HC) or C. 1 μg/mL HC (+HC) in serum-free medium and assayed for luciferase activity following a 48 hour incubation. Bars represent the mean of technical replicates, and error bars represent standard deviation (N = 3). For B., statistically significant changes in Ch25h promoter activity relative to the EV control for each reporter are indicated: one asterisk, p < 0.05 (significant); two asterisks, p < 0.005 (very significant); three asterisks, p < 0.0005 (very highly significant). For C., statistically significant changes in Ch25h promoter activity in response to EV and GRwt transfections are indicated relative to the EV transfection for each reporter from the corresponding -HC experiment in B.