DiMNF-mediated repression of CD55 mRNA expression occurs through an AHR-dependent pathway. A to C, Huh7 cells were pretreated with vehicle or 10 nM TCDD (A), 10 nM SGA360 (B), or 500 nM GNF351 (C) for 1 h, followed by treatment with 10 ng/ml of IL1β, and quantitative real-time PCR was performed to measure the expression of CD55 mRNA. D, Hep3B cells targeted with either control or AHR-specific siRNA were incubated with vehicle or 10 μM DiMNF for 1 h before treatment with IL1β for 24 h, and CD55 mRNA expression was measured by quantitative real-time PCR. Data represent mean mRNA expression level ± S.E.M. normalized to constitutively expressed ribosomal L13 mRNA. Statistical significance is indicated: *, p < 0.05.