Glycine-extended gastrin activates two independent tyrosine-kinases in upstream of p85/p110 phosphatidylinositol 3-kinase in human colonic tumour cells.
OBJECTIVE
To investigate whether Src, JAK2 and phosphatidylinositol 3-kinase (PI3K) pathways are involved in the proliferation of human colonic tumour cells induced by glycine-extended gastrin (G-gly), the precursor of the mature amidated gastrin and to elucidate the molecular interaction between these three kinases in response to this peptide.


METHODS
Using the human colonic tumour cell line HCT116 as a model, we first measured the activation of PI3K, p60-Src and JAK2 in response to G-gly by in vitro kinase assays. Then we investigated the involvement of these kinases in G-gly-induced cell proliferation by MTT test.


RESULTS
G-gly stimulation induced p60-Src, JAK2 and PI3K activation in HCT116. The different pathways were involved in proliferation of human colon cancer cells induced by G-gly. Furthermore, we found that both Src and JAK2 were necessary to PI3K regulation by this peptide. However, we did not find any cross-talk between the two tyrosine kinases.


CONCLUSIONS
Our results suggest that the p60-Src/PI3K and JAK2/PI3K pathways act independently to mediate G-gly proliferative effect on human colonic tumour cells.
Ferrand
Audrey
A
Institut Louis Bugnard, BP 84225, Unite INSERM 531, Biologie et Pathologie Digestives, 31432 Toulouse Cedex 4, France.
Kowalski-Chauvel
Aline
A
Pannequin
Julie
J
Bertrand
Claudine
C
Fourmy
Daniel
D
Dufresne
Marlene
M
Seva
Catherine
C
D049109:Cell Proliferation / Q000187:drug effects; D003110:Colonic Neoplasms / Q000201:enzymology* / Q000473:pathology; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation / Q000187:drug effects; D005755:Gastrins / Q000494:pharmacology*; D045325:HCT116 Cells; D006801:Humans; D047468:Immunoprecipitation; D053614:Janus Kinase 2; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology*; D011505:Protein-Tyrosine Kinases / Q000502:physiology*; D011518:Proto-Oncogene Proteins / Q000502:physiology*; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*
D005755:Gastrins; D011518:Proto-Oncogene Proteins; D019869:Phosphatidylinositol 3-Kinases; D011505:Protein-Tyrosine Kinases; C507924:JAK2 protein, human; D053614:Janus Kinase 2; D016392:Proto-Oncogene Proteins pp60(c-src)