Table 1.
ER-subtype selectivity of genistein, Br-ERβ-041, and PPT in SKBR3 cells transiently co-transfected with a estrogen-responsive reporter gene plasmid (pGudLuc7.ERE) and either a ERα or ERβ expression plasmid.
| ERα | ERβ | |||
|---|---|---|---|---|
| Chemical | EC50 [M] | Maximal Inductiona | EC50 [M] | Maximal Inductiona |
| E2 | 8.5 ± 2.2 × 10−12 | 100 ± 8% | 7.5 ± 2.9 × 10−11 | 100 ± 7% |
| Genistein | 2.6 ± 0.8 × 10−7 | 101 ± 3% | 4.4 ± 1.9 × 10−8 | 199 ± 25%* |
| Br-ERβ-041 | 9.7 ± 1.3 × 10−7 | 90 ± 8% | 5.4 ± 0.9 × 10−8 | 93 ± 7% |
| PPT | 2.5 ± 0.2 × 10−10 | 92 ± 16% | No induction | No induction |
a
Luciferase induction is expressed as the mean ± SD of three individual experiments (with chemicals analyzed in triplicate) and values are presented as the percent of maximum luciferase induction obtained with E2 (1 nM). Maximum luciferase induction by genistein, Br-ERβ-041, and PPT was observed at concentration of 3.16 µM, 10 µM, and 10 nM, respectively.
*
Significantly different from that of 1 nM E2 at p < 0.05 as determined by Student’s t-test.