(E) Loss of AhR reduces SMAD3 expression levels. SMAD3 expression has been investigated in SKMel28 cells AhR wild-type (WT) or knock-out (KO). SKMel28R, have been obtained from SKMel28S by chronic exposure to non-lethal doses of BRAFi R for BRAFi-resistant SKMel28 cells and S for sensitive. 