Fig. 6.

Treatment with herbimycin A inhibits the activation of IκB kinase (IKK) and NF-κB, and the expression of interleukin (IL)-8 and cyclo-oxygenase-2 (COX-2) in HT-29 cells stimulated with Bacteroides fragilis (BFT). (a) HT-29 cells were incubated in the absence or presence of herbimycin A (0·5 μM) for 24 h before treatment of BFT (100 ng/ml) for 24 h. IKK kinase activity was measured using a HTScan IKK-β kinase assay kit. Data are expressed as mean fold induction ± standard error of the mean (s.e.m.) of kinase activity relative to untreated controls (n = 5). (b, c, and d) HT-29 cells were transfected with p2x nuclear factor kappaB (NF-κB)-, pIL8-, or pCOX-2-luciferase transcriptional reporters in the absence or presence of herbimycin A (0·5 μM) for 24 h. BFT (100 ng/ml) was added to the transfected cells for 1 h (NF-κB, b) or 8 h (IL-8 and COX-2, c,d). Data are expressed as mean fold induction ± s.e.m. of luciferase activity relative to untreated controls (n = 5). The mean fold induction of β-actin reporter gene activity relative to untreated controls remained relatively constant throughout each experiment. Asterisks indicate values of BFT + herbimycin A that are significantly different from those of BFT alone (P < 0·05).