Fig. 1.

CpdA-mediated transrepression of the IL-6 gene promoter in fibroblast cells is only efficient in absence of a functional AP-1-response element. a, b Subconfluent L929sA cell monolayers stably transfected with the indicated promoter reporter gene constructs were grown in 24-well plates. The point-mutated variant is indicated by its mutated transcription factor-binding site, i.e., AP-1, between brackets. c Similar to panels (a) and (b), but with inductions performed on L929sA cells with a stably integrated recombinant (IL6κB)₃50hu.IL6P-luc+ reporter construct. Cells were left untreated or treated with 2,000 IU/ml TNF, for 5 h, preceded by a 1 h treatment with solvent (as indicated by the minus sign), DEX (1 μM) or CpdA (1 or 10 μM). At the end of the induction, cell lysates were assayed for reporter gene activities. Total solvent concentration was kept similar in all conditions. The experiments are carried out in triplicate or quadruplicate. Results are shown ± SD and are representative of two to four independent experiments. **p < 0.01, ***p < 0.001. For (a) comparisons versus the control lane are depicted by ‘#’ and comparisons versus the respective pro-inflammatory stimulus TNF are depicted by ‘§’. For b and c, comparisons were made vs. TNF