This figure shows the effect of TNF-α from the apical and basal sides on gene transcription. Caco-2 cells were grown in a 6-transwell system and stimulated with TNF-α (50 ng/mL) to induce an up-regulation of several selected genes involved in inflammation. Only basolateral stimulation with TNF-α (TNF-α bl) resulted in a significant up-regulation while apical stimulation with TNF-α (TNF-α ap) did not show any significant effect (p > 0.05). Data are expressed as mean and SD of n = 3 experiments. Asterisks assign statistically different values comparing apical and basolateral stimulation (*p < 0.05; **p < 0.01; ***p < 0.001).