Influence of gastrin on the expression of cyclooxygenase-2, hepatocyte growth factor and apoptosis-related proteins in gastric epithelial cells.
BACKGROUND
Several studies have shown a link between gastrin and gastric cancer, both in humans and animals, especially infected with Helicobacter pylori (H. pylori). However, the exact role of hypergastrinemia in gastric carcinogenesis remains still undetermined. The aim of the present study was to evaluate the interaction between gastrin, cyclooxygenase-2 (COX-2), hepatocyte growth factor (HGF) and apoptosis-related proteins (Bax, Bcl-2, caspase-3, survivin) in cultured gastric epithelial cancer cells.


METHODS
In the present study, gastric cultured cancer cells (KATO III cells) were exposed to increasing concentrations of gastrin (1-1000 nM). Cells incubated with culture medium alone, without added gastrin, served as controls. Using RT-PCR and Western blot, we examined the mRNA and protein expression for COX-2, HGF and apoptosis-related proteins (Bax, Bcl-2, caspase-3 and survivin). In addition, the gene expression of gastrin and gastrin receptor (CCK-2) as well as the release of gastrin in culture medium in the unstimulated cells were examined by RT-PCR and RIA, respectively. The apoptosis rate in cells was measured by flow cytometric analysis.


RESULTS
The present study shows that the gastric cultured epithelial cells exhibit the expression of gastrin and CCK-2 receptors and release of gastrin into the culture medium. The epithelial gastric cancer cells incubated with gastrin showed a concentration-dependent increase of COX-2 and HGF expression. Although no significant changes in apoptosis rate were observed, the exposure of these cells was associated with a dose-dependent increase in the expression of antiapoptotic proteins Bcl-2 and survivin.


CONCLUSIONS
This study demonstrates that 1) gastrin stimulates the gene and protein expression of COX-2 and HGF in human cultured gastric cancer cells and 2) gastrin shows antiapoptotic activity through the upregulation of Bcl-2 and survivin.
Konturek
P C
PC
Department of Medicine I, University Erlangen-Nuremberg, Erlangen, Germany. pkonturek@aol.com
Kania
J
J
Kukharsky
V
V
Ocker
S
S
Hahn
E G
EG
Konturek
S J
SJ
D017209:Apoptosis; D018279:Carcinoma, Signet Ring Cell / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D053148:Caspase 3; D020169:Caspases / Q000096:biosynthesis; D051546:Cyclooxygenase 2; D004273:DNA, Neoplasm / Q000096:biosynthesis / Q000235:genetics; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D005755:Gastrins / Q000502:physiology*; D005786:Gene Expression Regulation; D017228:Hepatocyte Growth Factor / Q000096:biosynthesis*; D006801:Humans; D066298:In Vitro Techniques; D051034:Inhibitor of Apoptosis Proteins; D007527:Isoenzymes / Q000096:biosynthesis*; D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins / Q000096:biosynthesis; D009363:Neoplasm Proteins; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis*; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D011949:Receptors, Cholecystokinin / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D000077022:Survivin; D014407:Tumor Cells, Cultured; D015854:Up-Regulation
C107489:BIRC5 protein, human; D004273:DNA, Neoplasm; D005755:Gastrins; D051034:Inhibitor of Apoptosis Proteins; D007527:Isoenzymes; D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D011949:Receptors, Cholecystokinin; D000077022:Survivin; D017228:Hepatocyte Growth Factor; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases