FIGURE 3 .

RA reduces the recruitment of AP-1 factors to the COX-2/CRE. The binding of c-Jun and c-Fos to a promoter segment of the human COX-2 promoter harboring a CRE (5′-TTCGTCA-3′) was examined in colon HCT-29 (A,B) and breast MCF-7 (C,D) cancer cells using a DNA-protein binding assay. Nuclear extracts were obtained from cells cotreated for 3 h with TPA (0.1 μmol/L) in the presence (+) or absence (−) of RA (10 μmol/L). Values are means + SE of triplicates from 2, n = 2, independent experiments. Means without a common letter differ, P < 0.05.