Luciferase reporter assays. The specificity of the COX-2 and Ki-67 promoter was confirmed using a dual luciferase reporter assay, allowing the analysis of test promoters via firefly luciferase activity and normalization of transfection efficiency via Renilla reniformis luciferase driven by the constitutive CMV-IE promoter in a single-well. Promoter activity was measured in subconfluent or G0/G1-arrested cells. To examine whether adenoviral gene products influence the promoter activity cells were infected with Ad5 after transfection with the reporter plasmids. The activity of the COX-2 and Ki-67 promoter was normalized to that of the CMV-IE promoter. Data are presented as mean ± SD from four independent experiments.