Fig. 2.

Effects of delphinidin on TPA-induced COX-2 expression, PGE₂ production, mRNA expression, and COX-2 promoter activity in JB6 P+ cells. A, Delphinidin downregulates TPA-induced COX-2 expression in JB6 P+ cells. JB6 P+ cells were treated for 30 min with delphinidin at the indicated concentrations (0, 5, 10, 20 μM) before being exposed to TPA for an additional 4 h. Cells were lysed, and the expression of COX-2 was analyzed by a Western blot assay as described in “Materials and Methods”. B, Delphinidin inhibits TPA-induced production of PGE₂ in JB6 P+ cells. JB6 P+ cells were pretreated with delphinidin at the indicated concentrations (0, 10, 20 μM) for 30 min before incubation with TPA for 16 h. PGE₂ generation was determined by a PGE₂ assay kit as described in “Materials and Methods”. The asterisk (*) indicates a significant difference (p < 0.01) between groups treated with TPA and delphinidin and the group exposed to TPA alone. C, Delphinidin inhibits TPA-induced COX-2 mRNA expression in JB6 P+ cells. Cells were treated for 2 h with TPA alone or together with delphinidin at the indicated concentrations (0, 10, 20 μM). The COX-2 mRNA level was determined by RT-PCR as described in “Materials and Methods”. Data are representative of two independent experiments. D, Delphinidin inhibits TPA-induced COX-2 promoter activity in JB6 P+ cells. JB6 P+ cells, which were stably transfected with COX-2 luciferase reporter plasmids, were pretreated with delphinidin for 30 min at the indicated concentrations (0, 5, 10, 20 μM) before being exposed to TPA for 24 h. The relative COX-2 activity was measured by a luciferase assay as described in “Materials and Methods”. The asterisk (*) indicates a significant difference (p < 0.01) between groups treated with TPA and delphinidin and the group exposed to TPA alone.