Mechanisms involved in Helicobacter pylori-induced interleukin-8 production by a gastric cancer cell line, MKN45

Miki Aihara, Daisuke Tsuchimoto, Hisao Takizawa, Atsushi Azuma, Hirokazu Wakebe, Yasukazu Ohmoto, Kenichi Imagawa, Mikio Kikuchi, Naofumi Mukaida, Kouji Matsushima

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Abstract

Accumulating evidence suggests an important role of interleukin-8 (IL- 8) in Helicobacter pylori infection-associated chronic atrophic gastritis and peptic ulcer. We observed in this study that a gastric cancer-derived cell line, MKN45, produced a massive amount of IL-8 upon coculture with live H. pylori but not with killed H. pylori, H. pylori culture supernatants, or live H. pylori separated by a permeable membrane, indicating that IL-8 production requires a direct contact between the cells and live bacteria. Moreover, the tyrosine kinase inhibitor herbimycin but neither a protein kinase C inhibitor (staurosporine) nor a protein kinase A inhibitor (H89) inhibited IL-8 production by MKN45 cells cocultured with live bacteria, suggesting the involvement of a tyrosine kinase(s) in H. pylori-induced IL-8 production. In addition, coculture of H. pylori induced IL-8 mRNA expression in MKN45 cells and an increase in luciferase activity in cells which were transfected with a luciferase expression vector linked with a 5'-flanking region of the IL-8 gene (bp -133 to +44), indicating that the induction of IL-8 production occurred at the transcriptional level. This region contain three cis elements important for induction of IL-8 gene expression: AP-1 (-126 to -120 bp), NF- IL6 (-94 to -81 bp), and NF-κB (-80 to -70 bp) binding sites. Mutation of the NF-κB binding site abrogated completely the induction of luciferase activity, whereas that of the AP-1 site partially reduced the induction. However, mutation of the NF-IL6 binding site resulted in no decrease in the induction of luciferase activity. Moreover, specific NF-κB complexes were detected in the nuclear proteins extracted from MKN45 cells which were infected with H. pylori. Collectively, these results suggest that H. pylori induced the activation of NF-κB as well as AP-1, leading to IL-8 gene transcription.

Original languageEnglish
Pages (from-to)3218-3224
Number of pages7
JournalInfection and Immunity
Volume65
Issue number8
DOIs
Publication statusPublished - 1997

All Science Journal Classification (ASJC) codes

  • Parasitology
  • Microbiology
  • Immunology
  • Infectious Diseases

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    Aihara, M., Tsuchimoto, D., Takizawa, H., Azuma, A., Wakebe, H., Ohmoto, Y., Imagawa, K., Kikuchi, M., Mukaida, N., & Matsushima, K. (1997). Mechanisms involved in Helicobacter pylori-induced interleukin-8 production by a gastric cancer cell line, MKN45. Infection and Immunity, 65(8), 3218-3224. https://doi.org/10.1128/iai.65.8.3218-3224.1997