Figure 2.

Effect of TAM and TAM metabolites on PGR gene expression in MCF-7 cells. Cells were incubated with 1 × 10⁻¹⁰ M E₂ for 12 h at 37°C in 5% CO₂. Total RNA was extracted and PGR mRNA levels were determined by RT-PCR as described in the Methods section. PGR mRNA levels were expressed as the fold-induction of PGR mRNA levels observed for untreated cells (media). (A) PGR gene expression in E₂-induced MCF-7 cells treated with TAM and 4-OH-TAM isomers or glucuronides; (B) PGR gene expression in E₂-induced MCF-7 cells treated with endoxifen isomers or glucuronides. The E₂ positive control, the media alone, and vehicle negative control are shown on both panels. E₂, cells incubated with 1 × 10⁻¹⁰ M E₂; vehicle, cells incubated with 0.1% DMSO; trans-4-OH, cells incubated with trans-4-OH- TAM; cis-4-OH, cells incubated with cis-4-OH-TAM, trans-4-OH-O, cells incubated with trans-TAM-4-O-glucuronide; cis-4-OH-O, cells incubated with cis-TAM-4-O-glucuronide; trans-4-OH-N, cells incubated with trans-4-OH-TAM-N⁺-glucuronide; cis-4-OH-N, cells incubated with cis-4-OH-TAM-N⁺-glucuronide; trans-E, cells incubated with trans-endoxifen; cis-E, cells incubated with cis-endoxifen; trans-E-O, cells incubated with trans-endoxifen-O-glucuronide; cis-E-O, cells incubated with cis-endoxifen-O-glucuronide; TAM, cells incubated with TAM; TAM-N, cells incubated with TAM-N-glucuronide. The figure legend describes the concentration of TAM or TAM metabolite used in this experiment. The mean ± standard error is shown for three experiments.