Involvement of MMP-7 in invasion of pancreatic cancer cells through activation of the EGFR mediated MEK-ERK signal transduction pathway.
OBJECTIVE
To clarify the involvement of matrix metalloproteinase-7 (MMP-7) in cell dissociation and the subsequent invasion of pancreatic cancer cells.


METHODS
Western blotting, in vitro invasion assay, immunocytochemistry, and immunohistochemistry were performed in pancreatic cancer cell lines or pancreatic cancer tissue.


RESULTS
The active form of the MMP-7 protein was expressed exclusively in the conditioned medium of dissociated (PC-1.0 and AsPC-1) pancreatic cancer cells, whereas proMMP-7 protein was only detected in the conditioned medium of non-dissociated (PC-1 and Capan-2) cells. Both intracellular and conditioned medium localised MMP-7 was greatly reduced by treatment with the epidermal growth factor receptor (EGFR) inhibitor AG1478 and the mitogen activated protein kinase kinase (MEK) inhibitor U0126 in pancreatic cancer cells. MMP-7 treatment significantly induced the disruption of tight junction (TJ) structures and subsequent cell dissociation, and activation of the EGFR mediated MEK- ERK (extracellular signal regulated protein kinase) signalling pathway in the non-dissociated pancreatic cancer cells. Moreover, the strong in vitro invasiveness of dissociated cells was inhibited by AG1478 and U0126 treatment, whereas the weak invasiveness of non-dissociated cells was apparently induced by MMP-7 treatment. In addition, MMP-7 expression was stronger at the invasive front than at the centre of human pancreatic tumours.


CONCLUSIONS
MMP-7 is involved in cell dissociation and the subsequent invasion of pancreatic cancer cells. It induces the disruption of TJ structures and forms a positive feedback loop with activation of the EGFR mediated MEK-ERK signalling pathway.
Tan
X
X
Department of Gastroenterological Surgery, Graduate School of Medical Sciences, Kumamoto University, Kumamoto 860-8556, Japan. tanxd@hotmail.com
Egami
H
H
Abe
M
M
Nozawa
F
F
Hirota
M
M
Ogawa
M
M
D000230:Adenocarcinoma / Q000201:enzymology / Q000473:pathology*; D000328:Adult; D000368:Aged; D015153:Blotting, Western; D002070:Butadienes / Q000494:pharmacology; D017077:Culture Media, Conditioned; D015536:Down-Regulation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D066246:ErbB Receptors / Q000502:physiology*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D020783:Matrix Metalloproteinase 7 / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D008875:Middle Aged; D020929:Mitogen-Activated Protein Kinase Kinases / Q000502:physiology; D009361:Neoplasm Invasiveness; D009570:Nitriles / Q000494:pharmacology; D010190:Pancreatic Neoplasms / Q000201:enzymology / Q000473:pathology*; D011799:Quinazolines; D015398:Signal Transduction; D019108:Tight Junctions; D014407:Tumor Cells, Cultured; D020032:Tyrphostins / Q000494:pharmacology
D002070:Butadienes; D017077:Culture Media, Conditioned; D004791:Enzyme Inhibitors; D009570:Nitriles; D011799:Quinazolines; D020032:Tyrphostins; C113580:U 0126; C101044:RTKI cpd; D066246:ErbB Receptors; D048049:Extracellular Signal-Regulated MAP Kinases; D020929:Mitogen-Activated Protein Kinase Kinases; D020783:Matrix Metalloproteinase 7