Figure 7

p21 mediates growth effects of androgen receptor (AR) ligand in MCF-10A cells. (A) MCF-10A p21^-/- cells were stably transfected with an AR cDNA, and lysates from single-cell clones were probed for AR expression by western blotting. As a negative control, MCF-10A p21^-/- cells were also transfected with empty vector (p21^-/- plus vector) and isolated as single-cell clones. Expression of AR was compared with ARIBE cells, which have wild-type p21. MDA-MB-453 and LNCaP cell lysates served as positive controls for AR expression. All lysates were also probed with GAPDH antibody as a loading control. (B) The p21^-/- (left) and p21 wild-type (right) cells were cultured in normal propagation media with 20 ng/ml epidermal growth factor (EGF), and treated with 1 nmol/l R1881. Cells were counted after 4 days of treatment, and normalized to values of cells counted on the day of drug addition (day 0). Error bars represent the standard deviation of the mean of three independent cell counts. The growth difference between p21^-/- AR-expressing cells and p21-wild-type AR-expressing cells was significant by one-way analysis of variance (ANOVA) (*P < 0.001). (C) Cells were cultured under normal propagation conditions except for the absence of EGF from the medium. Cells were treated with vehicle or drugs as described above. Cells were counted after 8 days of treatment, and normalized to values of cells counted on the day of drug addition (day 0). Error bars represent the standard deviation of the mean of three independent cell counts. The growth difference between p21^-/- AR-expressing cells and p21-wild-type AR-expressing cells was significant by one-way ANOVA (*P < 0.01).