Gastrin-mediated interleukin-8 and cyclooxygenase-2 gene expression: differential transcriptional and posttranscriptional mechanisms

Gastroenterology. 2008 Apr;134(4):1070-82. doi: 10.1053/j.gastro.2008.01.040. Epub 2008 Jan 18.


Background & aims: Gastrin induces the expression of cyclooxygenase (COX)-2 and interleukin (IL)-8; however, the mechanism(s), especially in gastric epithelial cells, is not well understood. Here, we have determined the intracellular mechanisms mediating gastrin-dependent gene expression.

Methods: AGS-E human gastric cancer cell line stably expressing cholecystokinin-2 receptor was treated with amidated gastrin-17. Real-time polymerase chain reaction, Western blot, and enzyme-linked immunosorbent assay were performed to determine COX-2 and IL-8 expression and Akt, Erk, and p38 phosphorylation. Gene promoter activity was determined by luciferase assay. Electrophoretic mobility shift assay analysis was performed for nuclear factor kappaB (NF-kappaB) and activator protein-1 activity. RNA stability was determined after actinomycin D treatment. HuR localization was determined by immunocytochemistry.

Results: Gastrin induced COX-2 and IL-8 expression in AGS-E cells, which was inhibited by phosphatidylinositol 3' kinase (PI3K) and p38 inhibitors. Gastrin-mediated Akt activation was observed to be downstream of p38. IL-8 expression was dependent on COX-2-mediated prostaglandin E(2) synthesis. In the presence of an NF-kappaB inhibitor MG132, IL-8 transcription was inhibited, but not that of COX-2. This was confirmed after knockdown of the p65 RelA subunit of NF-kappaB. Further studies showed that COX-2 gene transcription is regulated by activator protein-1. Gastrin increased the stability of both COX-2 and IL-8 messenger RNA (mRNA) in a p38-dependent manner, the half-life increasing from 31 minutes to 8 hours and approximately 4 hours, respectively. Gastrin, through p38 activity, also enhanced HuR expression, nucleocytoplasmic translocation, and enhanced COX-2 mRNA binding.

Conclusions: Gastrin differentially induces COX-2 and IL-8 expression at the transcriptional and posttranscriptional levels by PI3K and p38 mitogen-activated protein kinase pathways, respectively.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Adenocarcinoma / genetics
  • Adenocarcinoma / metabolism
  • Adenocarcinoma / pathology
  • Blotting, Western
  • Cell Line, Tumor
  • Cyclooxygenase 2 / biosynthesis
  • Cyclooxygenase 2 / drug effects
  • Cyclooxygenase 2 / genetics*
  • Dinoprostone / biosynthesis
  • Electrophoretic Mobility Shift Assay
  • Enzyme-Linked Immunosorbent Assay
  • Gastric Mucosa / drug effects
  • Gastric Mucosa / metabolism*
  • Gastric Mucosa / pathology
  • Gastrins / pharmacology*
  • Gene Expression Regulation, Neoplastic*
  • Humans
  • Immunohistochemistry
  • Immunoprecipitation
  • Interleukin-8 / biosynthesis
  • Interleukin-8 / drug effects
  • Interleukin-8 / genetics*
  • Oncogene Protein v-akt
  • RNA Stability / drug effects
  • RNA, Neoplasm / genetics*
  • Stomach Neoplasms / genetics
  • Stomach Neoplasms / metabolism
  • Stomach Neoplasms / pathology
  • Transcription, Genetic / drug effects*
  • p38 Mitogen-Activated Protein Kinases / metabolism


  • Gastrins
  • Interleukin-8
  • RNA, Neoplasm
  • gastrin 17
  • Cyclooxygenase 2
  • Oncogene Protein v-akt
  • p38 Mitogen-Activated Protein Kinases
  • Dinoprostone