Functional muscarinic m3 receptor expressed in gastric cancer cells stimulates tyrosine phosphorylation and MAP kinase

Citation
M. Kodaira et al., Functional muscarinic m3 receptor expressed in gastric cancer cells stimulates tyrosine phosphorylation and MAP kinase, J GASTRO, 34(2), 1999, pp. 163-171
Citations number
55
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Gastroenerology and Hepatology
Journal title
JOURNAL OF GASTROENTEROLOGY
ISSN journal
0944-1174 → ACNP
Volume
34
Issue
2
Year of publication
1999
Pages
163 - 171
Database
ISI
SICI code
0944-1174(199904)34:2<163:FMMREI>2.0.ZU;2-Z
Abstract
Human gastric cancer cells were used to examine the trophic effect of the m uscarinic m3 receptor subtype. Expression of the m3 receptor was detected i n five of night cell lines examined, MKN-1, 7, 28, 74, and TMK-1 cells. An increase in intracellular Ca2+ in response to carbachol was observed in mor e than 90% of TMK-1 cells, allowing us to use these cells in the following experiments. Western blot analysis showed that carbachol predominantly phos phorylated tyrosine in a 100-kDa protein. While mitogen-activated protein ( MAP) kinase activity in the presence of 100 mu M carbachol or 10ng/ml trans forming growth factor (TGF)a was augmented to 15- to 60-fold of the baselin e level for 5 min, the activation was transient. Pretreatment of the cells with 1 mu M phorbol 12-myristate U-acetate abolished carbacol-induced MAP k inase activation, whereas no suppression was observed in the presence of 50 0 nM Calphostin C (Kyowa Medex, Tokyo Japan), a specific protein kinase C i nhibitor. No DNA synthesis or cell proliferation was observed in the presen ce of carbachol. These results indicate that stimulation of the m3 subtype leads to tyrosine phosphorylation and MAP kinase activation, but is unlikel y to have trophic effects in gastric mucosal cells.