Figure 4.

AhR expression and activation is associated with protection against breast cancer cell invasiveness. qPCR analysis of endogenous AhR expression. SKBR3 cells (panel A) and MDA MB-231 cells (panel B) were transfected either a nontargeting siRNA duplex (Control si) or one of two independent AhR siRNAs (AhR-si-1, AhR-si-2). After 24 h, cells were treated with vehicle (Veh) or TCDD (10 nm) for 24 h. Cells were harvested 48 h after transfection for total RNA, which was used for qPCR. Graphic data are represented as fold induction over vehicle (set at 1). Data points represent the average of triplicate amplification reactions for each condition in a representative experiment (n = 3 independent assays). Invasiveness of SKBR3 cells (panel C) and MDA MB-231 cells (panel D) in the modified Boyden chamber invasion assay. Before assay, cells were transfected with siRNAs for 48 h and administered Veh or TCDD (10 nm) for 24 h. Graphic data are represented as percent of Veh control (set at 100%). For panels C and D, a representative experiment (n = 3 independent assays) is shown. In panels A–D, *, P < 0.05 for comparison between Control si and AhR-si-1 and Control si and AhR-si-2 for each treatment (Veh or TCDD).