fig4

Figure 4. TGF-β stimulation of EMT programs enhances EGFR, IGF1R, and MAP kinase signaling in MCF-7 and BT474 cells. (A and B) MCF-7 cells were stimulated with TGF-β1 (5 ng/mL) as indicated. Afterward, the activation status of ERK1/2 and p38 MAPK was determined by immunoblotting; (C) BT474 cells were treated with TGF-β1 (5 ng/mL) for 0-96 h prior to monitoring the activation status ERK1/2 and p38 MAPK by immunoblotting. (D) MCF-7 cells were stimulated with TGF-β1 (5 ng/mL) in the absence or presence of the TβR-I inhibitor II (100 ng/mL) for 72 h. Afterward, the expression levels of EGFR and activation status of p38 MAPK and ERK1/2 were determined by immunoblotting; (E-G) pre- and post-EMT MCF-7 cells were treated with AG1478 (1 µmol/L; E), with IGF-1 (100 ng/mL; top), estradiol (0.1 nmol/L; middle), and EGF (100 ng/mL; bottom; F), or with IGF-1 (100 ng/mL) in the absence or presence of AG1024 (1 µmol/L; G) as indicated. Afterward, the expression levels of EGFR and activation status of ERK1/2 and IGF1R were determined by immunoblotting as indicated. Data are representative images from at least 3-independent experiments. TGF: transforming growth factor; EMT: epithelial-mesenchymal transition; IGF: insulin-like growth factor; EGFR: epidermal growth factor receptor