Fig. 2
Effect of glyceollins I and II on ER activation by luciferase assay. MCF-7 cells were transfected with an ERE-TK-luciferase reporter plasmid and a CMV-β-galactosidase plasmid as a control of transfection efficiency. The cells were then treated with 10−9 M E2 (white) and different doses of glyceollin I (light grey) or II (hard grey) either alone (a), in combination with ICI182,780 (b) or in combination with E2 (c). Moreover, cells were pretreated with 10−5 M GI or GII at different time indicated (3 h, 1 h and 0 h) before 10−9 M E2 adding (d). The results are expressed as the percentage of luciferase activity obtained with E2 treatment and are represented as the mean +/− SEM of four independent experiments. *p-value <0.05, **p-value <0.01 and ***p-value <0.001 with a Mann-Whitney test followed by Bonferroni correction for comparisons of the control vs the treatments (a) or for treatment with E2 vs the other compounds (c and d)