(A) A schematic diagram of the IL-8 promoter is indicated, demonstrating AP-1, C/EBPβ, and NF-κB binding sites. (B) MCF-7, MDA-231, and CA1a breast cancer cells were stably transduced with lentiviral shRNA constructs targeting EpCAM (shUTR) or an irrelevant nucleotide sequence (shSCR). To measure IL-8 promoter activity, transduced cells were transfected with constructs containing the IL-8 promoter fused to luciferase, and a transfection control construct, TK-renilla. Relative luciferase activity was analyzed using a dual-luciferase kit. (C) MDA-231 cells transduced with the indicated lentiviral constructs were transfected with non-promoter luciferase reporter constructs for AP-1, C/EBPβ, NF-κB, and transfection control TK-renilla. Relative luciferase activity was analyzed using a dual-luciferase kit (Promega). Asterisks indicate significance at P value <0.05 when compared to control.