Figure 4

MDA-MB-231 cells transfected with androgen receptor (AR) show growth inhibition when treated with androgen. (A) The breast cancer cell line MDA-MB-231 was transfected with an AR cDNA, and lysates from single-cell clones were analyzed for AR protein expression. Two representative clones are shown. MDA-MB-453 and LNCaP lysates served as positive controls for AR expression. Lysates were also probed with GAPDH as a loading control.(B) Two MDA-MB-231 clones transfected with AR (ARc3 and ARc4) and control cells (Vector) were treated with vehicle, 1 μmol/l of the MEK inhibitor U0126, 1 nmol/l of R1881, or a combination of R1881 and U0126. Cells were counted after 4 days of drug treatment, and normalized to counts of vehicle-treated control cells. Error bars represent the standard deviation of the mean of three independent counts. The growth difference between cells treated with R1881 and R1881 plus U0126 was significant by Student's two-tailed t-test (*P < 0.005).