fig5

Figure 5. TGF-β stimulation of EMT programs promotes tamoxifen resistance in MCF-7 cells. (A) Pre- and post-EMT MCF-7 organoids were treated with estradiol (0.1 nmol/L), tamoxifen (0.1 µmol/L), or fulvestrant (0.1 µmol/L) for 8 days, at which point photomicrographs were captured and analyzed on Image J to assess differences in organoid growth. Images are representative of 3-independent experiments, while data are the mean fold-changes (± SE; n = 3; *P < 0.05; Student's t-test; ×400); (B) pre- and post-EMT MCF-7 cells were treated with tamoxifen (0.1 µmol/L) in the absence or presence of TβR-I Inhibitor II (100 ng/mL; left), of AG1024 (1 µmol/L; middle), or of AG1478 (1 µmol/L; right) as indicated. Afterward, differences in cell growth and survival were analyzed by MTS assays. Data are the mean (± SE; n = 3; *P < 0.05; Student's t-test) growth relative to untreated pre-EMT cells (*P < 0.05; Student's t-test); (C-E) pre- and post-EMT MCF-7 cells were treated with tamoxifen (0.1 µmol/L) in the absence or presence of U0126 (10 µmol/L; left), of TβR-I Inhibitor II (100 ng/mL; middle), or AG1024 (1 µmol/L; right) for 10 days, at which point the number of surviving colonies in 11 random fields/plate was enumerated. Data are the mean (± SE; n = 3; *P < 0.05; Student's t-test). TGF: transforming growth factor; EMT: epithelial-mesenchymal transition; SE: standard error