Enhancement of uPA promoter transactivation activity by RAR and RXR. BAECs were cotransfected with UK promoter-luciferase (0.4 μg/dish; A) or DR5-luciferase (0.4 μg/dish; B) plus RAR and/or RXR expressing vectors (250 ng each/dish), along with pRL-CMV (Renilla luciferase, 100 ng/dish) as described in Materials and Methods. Total DNA transfected was adjusted to 1.225 μg/dish with pSG5. The next day of transfection, the cells were treated or untreated with 1 μmol/L atRA or 9cRA for 12 hours. Luciferase activity of each cell was measured using the Dual-Luciferase Reporter Assay System, and changes in firefly luciferase activity were calculated and plotted after normalization to Renilla luciferase activity. Sample 1, reporter only; sample 2, atRA; sample 3, RAR; sample 4, RAR + atRA; sample 5, RXR; sample 6, RXR + 9cRA; sample 7, RAR and RXR; sample 8, RAR and RXR + atRA; sample 9, RAR and RXR + 9cRA. Each number represents the average ± SD (n = 3). Each similar experiment was repeated three times and representative results are shown here.