Figure 2.

Growth Factor Activation of Wild-Type Vav3 Results in Ligand-Independent AR Transactivation

A and B, PC3 cells were transfected with AR, the reporter plasmid PSA promoter/enhancer-luc, and wild-type Vav3, or equimolar amounts of the empty vector (EV). Cells were treated with either vehicle, a combination of EGF (100 ng/ml) plus IGF (10 ng/ml) or EGF+IGF and bicalutamide (5 μm) (A) or with vehicle or R1881 (5 nm) (B). Luciferase activity was assayed 48 h after transfection. Data are representative of two experiments performed in triplicate (A) or more than six experiments performed in triplicate (B). The means of triplicate determinations are plotted (RLU ± sem). Significance was determined using a two-tailed Student’s t test and represents differences from vehicle vs. growth factor or hormone treatment (**, P < 0.01; ***, P < 0.001). C, Lysates from PC3 cells treated as in A were immunoblotted to assess AR levels. Actin is shown as a loading control. Bic, Bicalutamide; RLU, relative light units; Veh, vehicle.