Involvement of Ras and AP-1 in Helicobacter pylori-induced expression of COX-2 and iNOS in gastric epithelial AGS cells.
Helicobacter pylori (H. pylori) is an important risk factor for chronic gastritis, peptic ulcer, and gastric cancer. The genetic differences of H. pylori isolates play a role in the clinical outcome of the infection. Inflammatory genes including cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) are involved in H. pylori gastritis. Transcription factor AP-1 is composed of c-Fos and c-Jun and mediates inflammation and carcinogenesis. Ras acts as a regulator for AP-1 activation in various cells. We investigated whether H. pylori in a Korean isolate (HP99), a cagA ( + ), vacA ( + ) strain, induces the expression of c-Fos and c-Jun for AP-1 activation to induce COX-2 and iNOS and whether HP99-induced expressions of COX-2 and iNOS are mediated by Ras and AP-1, determined by the expressions of c-Fos and c-Jun, in gastric epithelial AGS cells, using transfection with mutant genes for Ras (ras N-17) and c-Jun (TAM-67). As a result, HP99 induced the expression of c-Fos and c-Jun and the expressions of COX-2 and iNOS in AGS cells. Transfection with mutant genes for Ras or c-Jun suppressed HP99-induced expressions of COX-2 and iNOS in AGS cells. In conclusion, H. pylori in a Korean isolate induces the expression of COX-2 and iNOS via AP-1 activation, which may be mediated by Ras and the expression of c-Fos and c-Jun in gastric epithelial cells.
Cho
Soon Ok
SO
Department of Pharmacology, Brain Korea 21 Project for Medical Sciences, Seoul, 120-752, Korea.
Lim
Joo Weon
JW
Kim
Kyung Hwan
KH
Kim
Hyeyoung
H
D000230:Adenocarcinoma / Q000235:genetics* / Q000473:pathology / Q000821:virology; D045744:Cell Line, Tumor; D051546:Cyclooxygenase 2 / Q000235:genetics*; D015232:Dinoprostone / Q000378:metabolism; D004790:Enzyme Induction / Q000235:genetics; D004847:Epithelial Cells / Q000378:metabolism / Q000821:virology; D005753:Gastric Mucosa / Q000378:metabolism / Q000821:virology; D005756:Gastritis / Q000235:genetics* / Q000473:pathology / Q000821:virology; D005786:Gene Expression Regulation / Q000235:genetics; D016481:Helicobacter Infections / Q000235:genetics* / Q000821:virology; D016480:Helicobacter pylori / Q000235:genetics*; D006801:Humans; D052247:Nitric Oxide Synthase Type II / Q000235:genetics*; D009573:Nitrites / Q000378:metabolism; D010437:Peptic Ulcer / Q000235:genetics* / Q000473:pathology* / Q000821:virology; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics*; D016755:Proto-Oncogene Proteins c-jun / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000235:genetics; D013274:Stomach Neoplasms / Q000235:genetics* / Q000473:pathology / Q000821:virology; D018808:Transcription Factor AP-1 / Q000502:physiology*; D014162:Transfection; D018631:ras Proteins / Q000502:physiology*
D009573:Nitrites; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D012333:RNA, Messenger; D018808:Transcription Factor AP-1; C496319:NOS2 protein, human; D052247:Nitric Oxide Synthase Type II; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D018631:ras Proteins; D015232:Dinoprostone