Neurotensin stimulates protein kinase C-dependent mitogenic signaling in human pancreatic carcinoma cell line PANC-1.
Neuropeptides and their corresponding G protein-coupled receptors are increasingly implicated in the autocrine/paracrine stimulation of growth of human cancers. Using K-Ras mutated human pancreatic ductal adenocarcinoma cell line PANC-1 as a model system, we demonstrate that neurotensin (NT) induced translocation of phosphorylated extracellular signal-regulated kinases (ERK-1 and ERK-2) to the nucleus, rapid dose-dependent activation of dual-specificity mitogen and ERK-1 and ERK-2 kinase-1/2 (MEK-1/2), and striking stimulation of c-Raf-1 but not pan-Ras. Furthermore, treatment of PANC-1 cells with protein kinase C (PKC) inhibitors, GF-1 and Ro 31-8220, completely abrogated NT-induced ERK-1 and ERK-2 activation, and significantly attenuated NT-induced c-Raf-1 stimulation. Interestingly, NT did not stimulate epidermal growth factor receptor transactivation, and epidermal growth factor receptor tyrosine kinase or Src inhibitors did not affect NT-induced ERK activation in PANC-1 cells. Our results indicate that NT potently stimulates c-Raf-1-MEK-ERK in PANC-1 cells through a PKC-dependent signaling pathway. Furthermore, we show that NT-induced DNA synthesis in PANC-1 cells is ERK-dependent. Finally, we demonstrate that NT stimulated clonal growth of PANC-1 cells in semisolid medium, which is abrogated by both GF-1 and the MEK-1/2 inhibitor, U0126. Collectively our results suggest that PKC-mediated stimulation of ERK-1 and ERK-2 play a pivotal role in NT-induced growth of PANC-1 cells harboring activating K-Ras mutation.
Guha
Sushovan
S
Department of Medicine, Division of Digestive Diseases, School of Medicine and Molecular Biology Institute, University of California, Los Angeles, California 90095, USA.
Lunn
J Adrian
JA
Santiskulvong
Chintda
C
Rozengurt
Enrique
E
D002070:Butadienes / Q000494:pharmacology; D021441:Carcinoma, Pancreatic Ductal / Q000201:enzymology* / Q000473:pathology; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002467:Cell Nucleus / Q000201:enzymology; D004273:DNA, Neoplasm / Q000096:biosynthesis / Q000235:genetics; D004268:DNA-Binding Proteins / Q000494:pharmacology; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism; D050981:Erythroid-Specific DNA-Binding Factors; D051418:Focal Adhesion Kinase 2; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D009496:Neurotensin / Q000494:pharmacology*; D009570:Nitriles / Q000494:pharmacology; D010190:Pancreatic Neoplasms / Q000201:enzymology* / Q000473:pathology; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D019908:Proto-Oncogene Proteins c-raf / Q000378:metabolism; D014157:Transcription Factors / Q000494:pharmacology; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured; D019061:src-Family Kinases / Q000378:metabolism
D002070:Butadienes; D004273:DNA, Neoplasm; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D050981:Erythroid-Specific DNA-Binding Factors; D009570:Nitriles; D014157:Transcription Factors; C113580:U 0126; D009496:Neurotensin; D066246:ErbB Receptors; D011505:Protein-Tyrosine Kinases; D051418:Focal Adhesion Kinase 2; D019061:src-Family Kinases; D019908:Proto-Oncogene Proteins c-raf; D011493:Protein Kinase C; D020928:Mitogen-Activated Protein Kinases