Gastrin promotes human colon cancer cell growth via CCK-2 receptor-mediated cyclooxygenase-2 induction and prostaglandin E2 production.
The present study investigates the effects of gastrin-17 on human colon cancer HT-29 cells to examine whether gastrin receptor (CCK-2), cyclooxygenase (COX-1, COX-2) isoforms and prostaglandin receptor pathways interact to control cell growth. Reverse transcription (RT)-polymerase chain reaction (PCR) analysis demonstrated that HT-29 cells are endowed with the naive expression of CCK-2 receptor (short splice variant), COX-1, COX-2 and prostaglandin EP(4) receptor, but not gastrin. Gastrin-17 significantly promoted cell growth and DNA synthesis. Both these stimulating effects were abolished by L-365,260 or GV150013 (CCK-2 receptor antagonists), but were unaffected by SC-560 (COX-1 inhibitor). L-745,337 (COX-2 inhibitor) or AH-23848B (EP(4) receptor antagonist) partly reversed gastrin-17-induced cell growth, while they fully antagonized the enhancing action on DNA synthesis. HT-29 cells responded to gastrin-17 with a significant increase in prostaglandin E(2) release. This enhancing effect was completely counteracted by L-365,260, GV150013 or L-745,337, while it was insensitive to cell incubation with SC-560. Exposure of HT-29 cells to gastrin-17 was followed by an increased phosphorylation of both extracellular regulated kinases (ERK-1/ERK-2) and Akt. Moreover, gastrin-17 enhanced the transcriptional activity of COX-2 gene promoter and stimulated COX-2 expression. These latter effects were antagonized by L-365,260 or GV150013, and could be blocked also by PD98059 (inhibitor of ERK-1/ERK-2 phosphorylation) or wortmannin (inhibitor of phosphatidylinositol 3-kinase). Analogously, gastrin-17-induced prostaglandin E(2) release was prevented by PD98059 or wortmannin. The present results suggest that (a) in human colon cancer cells endowed with CCK-2 receptors, gastrin-17 is able to enhance the transcriptional activity of COX-2 gene through the activation of ERK-1/ERK-2- and phosphatidylinositol 3-kinase/Akt-dependent pathways; (b) these stimulant actions lead to downstream increments of COX-2 expression, followed by prostaglandin E(2) production and EP(4) receptor activation; (c) the recruitment of COX-2/prostaglandin pathways contributes to the growth-promoting actions exerted by gastrin-17.
Colucci
Rocchina
R
Interdepartmental Center for Research in Clinical Pharmacology and Experimental Therapeutics, University of Pisa, Via Roma 55, 56126 Pisa, Italy.
Blandizzi
Corrado
C
Tanini
Marzia
M
Vassalle
Cristina
C
Breschi
Maria Cristina
MC
Del Tacca
Mario
M
D000963:Antimetabolites; D015153:Blotting, Western; D001973:Bromodeoxyuridine; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D003110:Colonic Neoplasms / Q000473:pathology*; D051546:Cyclooxygenase 2; D004247:DNA / Q000096:biosynthesis / Q000235:genetics; D015232:Dinoprostone / Q000096:biosynthesis*; D004790:Enzyme Induction / Q000187:drug effects; D005755:Gastrins / Q000494:pharmacology*; D019073:HT29 Cells; D006801:Humans; D007527:Isoenzymes / Q000096:biosynthesis; D008156:Luciferases; D008565:Membrane Proteins; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis*; D012313:RNA / Q000096:biosynthesis / Q000302:isolation & purification; D043887:Receptor, Cholecystokinin B / Q000037:antagonists & inhibitors / Q000187:drug effects*; D011982:Receptors, Prostaglandin / Q000187:drug effects; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects
D000963:Antimetabolites; D005755:Gastrins; D007527:Isoenzymes; D008565:Membrane Proteins; D043887:Receptor, Cholecystokinin B; D011982:Receptors, Prostaglandin; D012313:RNA; D004247:DNA; D008156:Luciferases; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D019869:Phosphatidylinositol 3-Kinases; D001973:Bromodeoxyuridine; D015232:Dinoprostone