FIGURE 2 .

RA represses transcription activity in colon HT-29 cancer cells. Cells were transiently transfected with a 3.9-Kb fragment of the human COX-2 promoter (A) or a plasmid (p1xAP-1) containing a segment of the collagenase-1 gene promoter that harbors a consensus TRE (B). Transfected cells were pretreated for 1 h with various amounts (5, 10, and 20 μmol/L) of RA, followed by cotreatment with TPA (0.1 μmol/L) for 6 h. Values are means + SE of triplicates from 2, n = 2, independent experiments. Means without a common letter differ, P < 0.05.