Fig. 2.

PPARγ activation is required for the ginsenoside Rf-mediated inhibition of hypoxia-induced COX-2 expression. (A) A549 cells were pretreated with vehicle or ginsenoside Rf (10 μM) and/or T0070907 (5 μM) for 1 h before treatment with hypoxia for 24 h. Total proteins were prepared, and protein levels of COX-2 were determined by Western blot. Proteins expression were normalized to β-actin content in each sample. (B) A549 cells were transiently transfected with the COX-2 luciferase reporter gene. The following day, A549 cells were cultured in medium containing vehicle or ginsenoside Rf (10 μM) and/or PPARγ antagonist T0070907 (5 μM) for 24 h under the hypoxia, and luciferase activities were determined. Values represent the mean ± SD (N = 3). All experiments were repeated at least three times. * represents p < 0.05, ** represents p < 0.01, *** represents p < 0.001. COX-2, cyclooxygenase-2; PPARγ, peroxisome proliferator–activated receptor gamma; SD, standard deviation.