Figure 2

ATRA increases the activity of the human COX-2 promoter and its effect is inhibited by RAR-pan-antagonist LE540 or MEK-1 inhibitor PD98059. (a) Schematic of the COX-2 human promoter construct phPES2 containing the promoter fragment -327 to +59.. (b) ATRA (10 μM, 24 h) increases the activity of the human COX-2 gene promoter transfected in SH-SY5Y human neuroblastoma cells. For comparison, the effect of IL-1β (10 ng/ml, 24 h) is also shown. COX-2 promoter activity was determined in triplicate in four separate experiments (for statistical purposes n = 4; *P < 0.01 vs other groups; **P < 0.01 vs control). (c) ATRA (10 μM, 24 h) increases the expression of RAR-β (left) and induces ERK1/2 phosphorylation (right). Normalized density ratio of either RAR-β or ERK1/2 over α-actin is indicated for each band. Each photograph represents at least three repeated experiments. (d) Inhibition of ATRA-induced COX-2 promoter activity by the RAR-pan-antagonist LE540 and the MEK-1 inhibitor PD98059. Transiently transfected cells were pre-incubated for 1 h with either 2.5 μM LE540 or 50 μM PD98059 and then with ATRA (10 μM, 24 h). COX-2 promoter activity was measured in triplicate in four separate experiments (for statistical purposes n = 4) (*P < 0.01 vs other groups)