Helicobacter pylori activates the proto-oncogene c-fos through SRE transactivation.
Epidemiological studies have demonstrated a strong association between Helicobacter pylori infection and gastric cancer. However, there have been few detailed studies on the mechanism of cellular proliferation by H. pylori. Thus, we examined activation of the proto-oncogene c-fos to elucidate the underlying mechanism of cell proliferation caused by H. pylori. Activation of c-fos was evaluated in human gastric cancer cells (TMK1) by Northern blot and reporter assays with deletion analysis of the c-fos transcriptional control region. c-fos promoter activation and transcription were enhanced when cocultured with cag-positive strains. H. pylori-mediated c-fos promoter activation was inhibited by MEK1/2 inhibitor (U0126). The deletion analysis indicated that serum response element (SRE) was required for the activation of c-fos by H. pylori. In conclusion, c-fos promoter activation and transcription were enhanced through the activation of extracellular signal-regulated kinases (ERK)/mitogen-activated protein kinase (MAPK) cascade in gastric cancer cells when cocultured with H. pylori possessing intact cag PAI. SRE is required for the activation of c-fos by H. pylori. These results suggest a direct involvement of H. pylori infection in cellular proliferation, which may play a role in neoplastic transformation.
Mitsuno
Yuzo
Y
Department of Gastroenterology, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan. MITSUNO-21M@h.u-tokyo.ac.jp
Maeda
Shin
S
Yoshida
Haruhiko
H
Hirata
Yoshihiro
Y
Ogura
Keiji
K
Akanuma
Masao
M
Kawabe
Takao
T
Shiratori
Yasushi
Y
Omata
Masao
M
D000328:Adult; D000368:Aged; D002070:Butadienes / Q000494:pharmacology; D004252:DNA Mutational Analysis; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D017930:Genes, Reporter; D016480:Helicobacter pylori / Q000302:isolation & purification / Q000472:pathogenicity*; D006801:Humans; D008297:Male; D008875:Middle Aged; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors; D009570:Nitriles / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D000090063:Proto-Oncogene Mas; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis / Q000235:genetics*; D012334:RNA, Neoplasm / Q000096:biosynthesis; D017384:Sequence Deletion; D027602:Serum Response Element; D013274:Stomach Neoplasms / Q000235:genetics / Q000378:metabolism / Q000821:virology*; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured
D002070:Butadienes; D004791:Enzyme Inhibitors; C000715470:MAS1 protein, human; D009570:Nitriles; D000090063:Proto-Oncogene Mas; D016760:Proto-Oncogene Proteins c-fos; D012334:RNA, Neoplasm; C113580:U 0126; D020929:Mitogen-Activated Protein Kinase Kinases