Ligand modulation of RAR activity with the pan-RAR agonist, at-RA and the pan-RAR antagonist AGN193109, induces reciprocal effects on NFκB signaling activity. WT-Line 1 tumor cells, transiently transfected with RAR or NFκB reporter constructs were exposed to at-RA +/- AGN193109 for 24 h at the indicated concentrations. The dose dependent induction of RAR reporter activity (A) and reciprocal repression of NFκB reporter activity (B) by at-RA is reversed by AGN193109. The results represent the average (+/- SEM) of 3 independent experiments. A consistent observation is the agonistic tendency of 10 μM AGN193109, in both RAR and NFκB reporter assays.