Glycine-extended gastrin inhibits apoptosis in colon cancer cells via separate activation of Akt and JNK pathways.
Glycine-extended gastrin (G-Gly) is produced by colon cancers and has growth promoting and anti-apoptotic effects in the colonic epithelium. We have examined the anti-apoptotic effects of G-Gly and the signal transduction pathways involved. G-Gly stimulated HT-29 cell proliferation in a concentration dependent manner and inhibited serum-starvation and celecoxib-induced apoptosis. Inhibition of signalling via c-Jun NH2-terminal kinase (JNK) with SP600125 or PI3-kinase/Akt with LY294002 abolished the effects of G-Gly. G-Gly significantly increased phosphorylation of both JNK and Akt. The JAK2 inhibitor AG490 abolished the anti-apoptotic effect of G-Gly and inhibited phosphorylation of Akt but not of JNK. G-Gly stimulated tyrosine phosphorylation of JAK2. G-Gly-increased activation of AP-1 was JNK-dependant and activation of STAT3 was JAK2-dependant. We conclude that G-Gly promotes growth and inhibits apoptosis in colon cancer cells. These effects are mediated via the JAK2, PI3-kinase/Akt and JNK pathways. Activation of JAK2 is upstream of Akt but not of JNK.
Beales
Ian L P
IL
Gastroenterology Unit, Norfolk and Norwich University Hospital, Norwich NR4 7UZ, United Kingdom. i.beales@uea.ac.uk
Ogunwobi
O
O
D000873:Anthracenes / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D000068579:Celecoxib; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D002867:Chromones / Q000494:pharmacology; D003110:Colonic Neoplasms; D005755:Gastrins / Q000494:pharmacology*; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000502:physiology*; D053614:Janus Kinase 2; D009025:Morpholines / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000502:physiology; D011518:Proto-Oncogene Proteins / Q000037:antagonists & inhibitors / Q000502:physiology; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors / Q000502:physiology*; D011720:Pyrazoles / Q000494:pharmacology; D050796:STAT3 Transcription Factor / Q000378:metabolism; D015398:Signal Transduction; D013449:Sulfonamides / Q000494:pharmacology; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism; D020032:Tyrphostins / Q000494:pharmacology
D000873:Anthracenes; D002867:Chromones; D005755:Gastrins; D009025:Morpholines; D011518:Proto-Oncogene Proteins; D011720:Pyrazoles; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D013449:Sulfonamides; D018808:Transcription Factor AP-1; D020032:Tyrphostins; C095512:alpha-cyano-(3,4-dihydroxy)-N-benzylcinnamide; C086854:glycine-extended gastrin 17; C432165:pyrazolanthrone; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D014443:Tyrosine; D019869:Phosphatidylinositol 3-Kinases; D011505:Protein-Tyrosine Kinases; C507924:JAK2 protein, human; D053614:Janus Kinase 2; D051057:Proto-Oncogene Proteins c-akt; D048031:JNK Mitogen-Activated Protein Kinases; D000068579:Celecoxib