Differential regulation of iron chelator-induced IL-8 synthesis via MAP kinase and NF-κB in immortalized and malignant oral keratinocytes

Abstract Background Interleukin-8 (IL-8) is a cytokine that plays an important role in tumor progression in a variety of cancer types; however, its regulation is not well understood in oral cancer cells. In the present study, we examined the expression and mechanism of IL-8 in which it is involved by treating immortalized (IHOK) and malignant human oral keratinocytes (HN12) cells with deferoxamine (DFO). Methods IL-8 production was measured by an enzyme-linked immunoabsorbent assay and reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. Electrophoretic mobility shift assays was used to determine NF-κB binding activity. Phosphorylation and degradation of the I-κB were analyized by Western blot. Results IHOK cells incubated with DFO showed increased expression of IL-8 mRNA, as well as higher release of the IL-8 protein. The up-regulation of DFO-induced IL-8 expression was higher in IHOK cells than in HN12 cells and was concentration-dependent. DFO acted additively with IL-1β to strongly up-regulate IL-8 in IHOK cells but not in HN12 cells. Accordingly, selective p38 and ERK1/2 inhibitors for both kinases abolished DFO-induced IL-8 expression in both IHOK and HN12 cells. Furthermore, DFO induced the degradation and phosphorylation of IκB, and activation of NF-κB. The IL-8 inducing effects of DFO were mediated by a nitric oxide donor (S-nitrosoglutathione), and by pyrrolidine dithiocarbamate, an inhibitor of NF-κB, as well as by wortmannin, which inhibits the phosphatidylinositol 3-kinase-dependent activation of NAD(P)H oxidase. Conclusion This results demonstrate that DFO-induced IL-8 acts via multiple signaling pathways in immortalized and malignant oral keratinocytes, and that the control of IL-8 may be an important target for immunotheraphy against human oral premalignant lesions.</p

A mast cell-ILC2-Th9 pathway promotes lung inflammation in cystic fibrosis

T helper 9 (Th9) cells contribute to lung inflammation and allergy as sources of interleukin-9 (IL-9). However, the mechanisms by which IL-9/Th9 mediate immunopathology in the lung are unknown. Here we report an IL-9-driven positive feedback loop that reinforces allergic inflammation. We show that IL-9 increases IL-2 production by mast cells, which leads to expansion of CD25 + type 2 innate lymphoid cells (ILC2) and subsequent activation of Th9 cells. Blocking IL-9 or inhibiting CD117 (c-Kit) signalling counteracts the pathogenic effect of the described IL-9-mast cell-IL-2 signalling axis. Overproduction of IL-9 is observed in expectorates from cystic fibrosis (CF) patients, and a sex-specific variant of IL-9 is predictive of allergic reactions in female patients. Our results suggest that blocking IL-9 may be a therapeutic strategy to ameliorate inflammation associated with microbial colonization in the lung, and offers a plausible explanation for gender differences in clinical outcomes of patients with CF