Fig. 3
From: Inhibition of TPL2 by interferon-α suppresses bladder cancer through activation of PDE4D
Induction of PDE4D by roflumilast potentiates anti-proliferation effect of IFN-α in vitro. (a) T24 cells were treated using the specific concentrations of roflumilast for 24 h. (b) T24 cells were treated with roflumilast (1 μM) for specific time points. (c) T24 cells were treated with roflumilast (1 μM) for specific time points. Intracellular cAMP levels and activity of immunoprecipitated PDE4D were detected. (d) T24 cells were treated with IFN-α (1 × 104 U/mL) and roflumilast (1 μM) either individually or in combination for 24 h. The level of PDE4D that interacted with IFNAR2 or IFNAR1 was detected by performing western blotting after co-immunoprecipitation using IFNAR2 or IFNAR1 antibodies. The expression levels of total PDE4D and β-tubulin in the cell lysates were used as loading control. (e) T24 cells were treated with IFN-α (1 × 104 U/mL) and roflumilast (1 μM) either individually or in combination for 24 h. The intracellular cAMP level and activity of total PDE4D were detected after immunoprecipitation using PDE4D antibody. (f, g) The cell viability (f) and PGE2 production (g) were detected after T24 cells were treated with IFN-α (1 × 104 U/mL) and roflumilast (1 μM) either individually or in combination for 72 h. Data represent the results of three independent experiments. Error bars indicate mean ± SD. *, P < 0.05; **, P < 0.01; #, P < 0.05 (t-test)