Fig. 3.

Effect of inhibitors of signalling pathways on transglutaminase 2 (TG2) induction by tumour necrosis factor (TNF)-α and interferon (IFN)-γ. Caco-2 and THP-1 cells were incubated for 24 h with specific inhibitors of signalling pathways: SP600125 (20 µM), SB203580 (10 µM), wortmannin (10 µM), Ly294002 (2 µM), sulphasalazine (10 µM) in the presence of TNF-α (10 ng/ml), IFN-γ (200 UI/ml) or the double stimulus TNF-α + IFN-γ. Level of TG2 transcripts was determined by quantitative real time polymerase chain reaction (RT–PCR). Results were normalized with the housekeeping gene β-actin and were referred to the non-stimulated control (value = 1). Data represent means ± standard error of the mean (n = 4). The Mann–Whitney U-test was performed: *P < 0·05; **P < 0·01 (asterisks on individual bars indicate comparison versus control). The inserted chart indicates the signalling pathways targeted by the inhibitors used.