AhR antagonists suppress 5F 203-mediated JNK phosphorylation in breast cancer cells. (A) MDA-MB-468 and (B) T47D cells were treated with 0.1% DMSO, αNF, NAC, SP600125, or 1 µM 5F 203 for 6 h or were pretreated for 1 h with 100 nM αNF, 20 mM NAC, or 25 µM SP600125 before being exposed to 1 µM 5F 203 for 6 h. Following treatment, cells were lysed, and protein content was determined and resolved using western blotting as described in Materials and Methods. Gel is of a representative blot. (C) Data is representative of three independent experiments. Graphs based on arbitrary units of ratios densitometry determinations for phospho-proteins relative to total protein and used to quantify the extent of activation. (D) MDA-MB-468 cells were exposed to 5F 203 (6 h) with or without EUK-134 or CH223191 pretreatment, and western blotting analysis was performed along with densitometry readings. Data represent the mean of at least three independent experiments; bars, SEM. Except where indicated by lines, *p < 0.05, **p < 0.01, and ***p < 0.001 compared to cells exposed to 5F 203 only.