VAF347 has no biologic effects in MM1 cells expressing reduced AhR levels. The graph shows CYP1A1 (top panel) or IL-6 (middle panel) RNA expression in cells infected with a control shRNA (sh-ctrl) or a sh-AhR retroviral construct. At the bottom, an immunoblot is shown demonstrating reduced AhR protein expression in sh-AhR–infected cells. The size of molecular weight protein standards is given in kilodaltons.