Differential regulation of iron chelator-induced IL-8 synthesis via MAP kinase and NF-kappaB in immortalized and malignant oral keratinocytes.
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-kappaB binding activity. Phosphorylation and degradation of the I-kappaB 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-1beta 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 IkappaB, and activation of NF-kappaB. The IL-8 inducing effects of DFO were mediated by a nitric oxide donor (S-nitrosoglutathione), and by pyrrolidine dithiocarbamate, an inhibitor of NF-kappaB, as well as by wortmannin, which inhibits the phosphatidylinositol 3-kinase-dependent activation of NAD(P)H oxidase.


CONCLUSIONS
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.
Lee
Hwa-Jeong
HJ
Department of Oral & Maxillofacial Pathology, College of Dentistry, Wonkwang University, Iksan, Republic of Korea. lhj0506@hotmail.com
Lee
Jun
J
Lee
Sun-Kyung
SK
Lee
Suk-Keun
SK
Kim
Eun-Cheol
EC
D002478:Cells, Cultured; D003676:Deferoxamine / Q000494:pharmacology; D006801:Humans; D016209:Interleukin-8 / Q000096:biosynthesis*; D007502:Iron Chelating Agents / Q000494:pharmacology; D015603:Keratinocytes / Q000187:drug effects* / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009062:Mouth Neoplasms / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D017262:Siderophores / Q000494:pharmacology; D015398:Signal Transduction
D016209:Interleukin-8; D007502:Iron Chelating Agents; D016328:NF-kappa B; D017262:Siderophores; D020928:Mitogen-Activated Protein Kinases; D003676:Deferoxamine