Fig. 8. Autocrine signaling in human mammary epithelial cells. (A) Cells were grown in 12-well dishes for 6 days with medium alone (control), mAb 225 (10 µg/ml), BB-2116 (10 µM) or EGF (2 nM). The medium was changed every other day and the cells were counted on day 6. (B) Cells were grown as described above with concentrations of BB-2116 ranging from 0.01 to 10 µM. Cell numbers were determined on day 6. Parallel cultures of cells in 60 mm dishes were treated with the same concentrations of BB-2116 and 20 µg/ml of mAb 225 for 18 hours. The medium was then collected and the TGF- levels were determined by RIA. Cell number was 2x10⁶ per dish. Error bars represent the SD of triplicate samples.