[Effect of gastrin on tyrosine phosphorylation of focal adhesion kinase in human gastric cancer cell line SGC7901].
OBJECTIVE
Gastrin contributes to the growth and proliferation of gastric cancer cells and it is related to the effect of tyrosine kinase. This study was to investigate the effect of gastrin on tyrosine phosphorylation of focal adhesion kinase (FAK) in human gastric cancer cell line SGC7901.


METHODS
The vector pCR3.1/GR, that expresses human gastrin receptor (GR) stably, was transfected into SGC7901 cells (SGC7901-GR). The expression of GR was tested by reverse transcription-polymerase chain reaction (RT-PCR). SGC7901-GR and SGC7901 cells were treated with L-365260, an antagonist of GR, and stimulated with gastrin at different concentrations for different time. The tyrosine phosphorylation level of FAK was detected by immunoprecipitation and Western blot.


RESULTS
When treated with different concentrations of gastrin for 1 min, the tyrosine phosphorylation levels of FAK were significantly higher in SGC7901-GR cells than in SGC7901 cells (0.64+/-0.06 vs. 0.40+/-0.05 at 0.1 nmol/L, 0.91+/-0.10 vs. 0.52+/-0.07 at 1 nmol/L, and 1.00+/-0.10 vs. 0.62+/-0.06 at 10 nmol/L, P<0.01). When treated with 10 nmol/L gastrin for different time, the tyrosine phosphorylation levels of FAK were also significantly higher in SGC7901-GR cells than in SGC7901 cells (0.72+/-0.08 vs. 0.59+/-0.05 at 1 min, 0.83+/-0.05 vs. 0.65+/-0.07 at 5 min, 0.88+/-0.06 vs. 0.58+/-0.03 at 10 min, and 1.00+/-0.08 vs. 0.47+/-0.10 at 20 min, P<0.05). L-365260 decreased the tyrosine phosphorylation levels of FAK from 1.00+/-0.07 to 0.72+/-0.07 in SGC7901-GR cells (P<0.01), and from 0.62+/-0.06 to 0.45+/-0.05 in SGC7901 cells (P<0.01). The protein levels of FAK in different cells remained unchanged during these experiments (P>0.05).


CONCLUSIONS
FAK is a pivotal signal transducer in downstream of gastrin with GR. Tyrosine phosphorylation is the symbol of FAK activation.
Li
Dan
D
Department of Gastroenterology, Union Hospital, Fujian Medical University, Fuzhou, Fujian, PR China. lidan2006@hotmail.com
Ding
Jian
J
Wang
Xiao-Zhong
XZ
D001570:Benzodiazepinones / Q000494:pharmacology; D045744:Cell Line, Tumor; D051417:Focal Adhesion Kinase 1 / Q000378:metabolism*; D005755:Gastrins / Q000494:pharmacology*; D005822:Genetic Vectors; D006801:Humans; D010671:Phenylurea Compounds / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D043887:Receptor, Cholecystokinin B / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D013274:Stomach Neoplasms / Q000378:metabolism* / Q000473:pathology; D014162:Transfection
D001570:Benzodiazepinones; D005755:Gastrins; D010671:Phenylurea Compounds; D043887:Receptor, Cholecystokinin B; C058121:L 365260; C013550:gastrin 17; D051417:Focal Adhesion Kinase 1; C496050:PTK2 protein, human