Effects of PGE2 on MMP-9 and MMP-2 expression and activity. (A) CD11c+ DCs were treated with PGE₂ (10⁻⁶ M), and RNA was extracted at different time points and subjected to MMP-9 real-time RT-PCR. One representative experiment of 2 is shown. (B,D) CD11c+ DCs were treated with different concentrations of PGE2 for 48 hours, followed by ELISA for secreted pro–MMP-9 and total-MMP-2. Data are representative of 3 independent experiments. (C) DCs were treated with PGE2 (10⁻⁶ M) for 48 hours in the presence or absence of MMP-2 inhibitor I (10⁻⁵ M) or MMP-9 inhibitor I (10⁻⁶ M). Supernatants were collected and subjected to a gelatinase activity assay. p-aminophenylmercuric acetate-activated human MMP-2 was used as a positive control. Data are representative of 3 independent experiments.