Helicobacter pylori-Induced invasion and angiogenesis of gastric cells is mediated by cyclooxygenase-2 induction through TLR2/TLR9 and promoter regulation

J Immunol. 2005 Dec 15;175(12):8242-52. doi: 10.4049/jimmunol.175.12.8242.

Abstract

Cyclooxygenase-2 (COX-2) plays a crucial role in Helicobacter pylori-associated gastric cancer. In this study, we report that H. pylori-induced COX-2 expression enhances the cancer cell invasion and angiogenesis via TLR2 and TLR9, which can be attenuated by the specific COX-2 inhibitor NS398 or celecoxib. The cAMP response element (CRE) and AP1 sites, but not kappaB on the COX-2 promoter, are involved in MAPKs-regulated COX-2 expression. Differential bindings of the CREB-1, ATF-2, c-jun to the CRE site, and the c-fos, c-jun, ATF-2 to the AP1 site are demonstrated by DNA affinity protein-binding, supershift, and chromatin immunoprecipitation assays. Activations of these transcription factors were attenuated by different MAPKs inhibitors. The mutants of TLR2, TLR9, or MAPKs inhibited H. pylori-induced COX-2 promoter, CRE, and AP-1 activities. MAPKs inhibitors attenuated the H. pylori-induced COX-2 mRNA and protein expressions. These results indicate that H. pylori acts through TLR2 and TLR9 to activate MAPKs, especially p38, and their downstream transcription factors (CREB-1, ATF-2, c-jun, and c-fos), resulting in the activations of CRE and AP-1 on the COX-2 promoter. These intracellular networks drive the COX-2-dependent PGE2 release and contribute to cell invasion and angiogenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line, Tumor
  • Cyclooxygenase 2 / genetics
  • Cyclooxygenase 2 / physiology*
  • Dinoprostone / metabolism
  • Helicobacter pylori*
  • Humans
  • Membrane Proteins / genetics
  • Membrane Proteins / physiology*
  • Neoplasm Invasiveness / pathology*
  • Neovascularization, Pathologic / enzymology
  • Neovascularization, Pathologic / virology*
  • Promoter Regions, Genetic
  • Stomach Neoplasms / pathology*
  • Stomach Neoplasms / virology*
  • Toll-Like Receptor 2 / physiology
  • Toll-Like Receptor 9 / physiology
  • Transcription Factor AP-1 / metabolism
  • Transcription Factors / metabolism

Substances

  • Membrane Proteins
  • TLR2 protein, human
  • TLR9 protein, human
  • Toll-Like Receptor 2
  • Toll-Like Receptor 9
  • Transcription Factor AP-1
  • Transcription Factors
  • Cyclooxygenase 2
  • PTGS2 protein, human
  • Dinoprostone