Roscovitine treatment or HDAC transfection abrogated COX-2 promoter activation. (A-B) Concentration-dependent inhibition of COX-2 promoter activity by roscovitine in HFb and RAW 264.7 with or without p300 transduction and PMA (A) or LPS (B) treatment. (C-D) Influence of HDAC-1 transfection on COX-2 promoter activity in HFb and RAW 264.7 cells with or without p300 transfection and PMA (C) or LPS (D) treatment. Transfection with an empty vector was included in each experiment as control. It yielded basal levels of promoter activities. Each bar denotes mean ± SEM of 3 experiments.