Figure 3.

Effects of prenyltransferase inhibitors on estrogen response element-dependent luciferase activity in HELN cells, transfected with estrogen receptor (ER) α or its mutants. Cells, deprived of estradiol (E2) for 4 days, were co-transfected with the Renilla luciferase plasmid and either HEG0 (full-length ERα), HEG19 (AF-1-deleted ERα), HEG7 (AF-2-deleted ERα) or pSG5 (empty vector). Five hours after transfection, cells were treated or not with FTI-277 (10 μM or dithiothreitol/dimethylsulfoxide vehicle), and 24 hours later they were stimulated with E2 (5 nM) or ethanol and treated or not with FTI-277 or GGTI-298 (10 μM or 5 μM, respectively, or dithiothreitol/dimethylsulfoxide vehicle). Luciferase activity was quantified 16 hours after E2 addition, as described in Materials and methods. Results are expressed in arbitrary units after normalization. Error bars indicate the mean values ± standard deviation from triplicate experiments, and the results are representative of three independent experiments. Results obtained show that prenylation inhibitors statistically increase or do not statistically increase the luciferase activity on their own compared with control cells (white bars) and statistically increase the luciferase activity induced by E2 compared with the activity induced by E2 alone (grey bars) in HELN cells transfected with ERα or its mutants (* P < 0.02).