ABSTRACT
Human pancreatic cancer invasion and metastasis have been found to correlate with increased levels of active matrix metalloproteinase 2 (MMP-2). The multifunctional cytokine transforming growth factor beta 1 (TGF-ß1) has been shown to increase both secretion of MMP-2 and invasion by several pancreatic cancer cell types. In the present study, we investigated the signaling pathway involved in TGF-ß1-promoted MMP-2 secretion and invasion by human pancreatic cancer cells SW1990. Using specific inhibitors, we found that stimulation of these tumor cells with TGF-ß1 induced secretion and activation of the collagenase MMP-2, which was required for TGF-ß1-stimulated invasion. Our results also indicate that signaling events involved in TGF-ß1-enhanced SW1990 invasiveness comprehend activation of Rac1 followed by generation of reactive oxygen species through nicotinamide adenine dinucleotide phosphate-oxidase, activation of nuclear factor-kappa beta, release of interleukin-6, and secretion and activation of MMP-2.
Subject(s)
Interleukin-6/metabolism , Matrix Metalloproteinase 2/metabolism , NF-kappa B/metabolism , Pancreatic Neoplasms/pathology , Protein-Tyrosine Kinases/metabolism , Proto-Oncogene Proteins/metabolism , Transforming Growth Factor beta1/metabolism , rac1 GTP-Binding Protein/metabolism , Cell Line, Tumor , Humans , Neoplasm Invasiveness , Pancreatic Neoplasms/metabolism , Transforming Growth Factor beta1/pharmacologyABSTRACT
AIM: To investigate chronic stress as a susceptibility factor for developing pancreatitis, as well as tumor necrosis factor-α (TNF-α) as a putative sensitizer. METHODS: Rat pancreatic acini were used to analyze the influence of TNF-α on submaximal (50 pmol/L) cholecystokinin (CCK) stimulation. Chronic restraint (4 h every day for 21 d) was used to evaluate the effects of submaximal (0.2 µg/kg per hour) cerulein stimulation on chronically stressed rats. RESULTS: In vitro exposure of pancreatic acini to TNF-α disorganized the actin cytoskeleton. This was further increased by TNF-α/CCK treatment, which additionally reduced amylase secretion, and increased trypsin and nuclear factor-κB activities in a protein-kinase-C δ and ε-dependent manner. TNF-α/CCK also enhanced caspases' activity and lactate dehydrogenase release, induced ATP loss, and augmented the ADP/ATP ratio. In vivo, rats under chronic restraint exhibited elevated serum and pancreatic TNF-α levels. Serum, pancreatic, and lung inflammatory parameters, as well as caspases'activity in pancreatic and lung tissue, were substantially enhanced in stressed/cerulein-treated rats, which also experienced tissues' ATP loss and greater ADP/ATP ratios. Histological examination revealed that stressed/cerulein-treated animals developed abundant pancreatic and lung edema, hemorrhage and leukocyte infiltrate, and pancreatic necrosis. Pancreatitis severity was greatly decreased by treating animals with an anti-TNF-α-antibody, which diminished all inflammatory parameters, histopathological scores, and apoptotic/necrotic markers in stressed/cerulein-treated rats. CONCLUSION: In rats, chronic stress increases susceptibility for developing pancreatitis, which involves TNF-α sensitization of pancreatic acinar cells to undergo injury by physiological cerulein stimulation.
Subject(s)
Pancreas, Exocrine/immunology , Pancreatitis/psychology , Stress, Psychological/complications , Tumor Necrosis Factor-alpha/metabolism , Actins/metabolism , Adenosine Diphosphate/metabolism , Adenosine Triphosphate/metabolism , Amylases/metabolism , Animals , Antibodies/pharmacology , Calcium Signaling , Caspases/metabolism , Ceruletide , Cholecystokinin/metabolism , Chronic Disease , Cytoskeleton/metabolism , Disease Models, Animal , Enzyme Activation , Lung Injury/etiology , Lung Injury/immunology , Lung Injury/psychology , Male , NF-kappa B/metabolism , Necrosis , Pancreas, Exocrine/drug effects , Pancreas, Exocrine/metabolism , Pancreas, Exocrine/pathology , Pancreatitis/chemically induced , Pancreatitis/immunology , Pancreatitis/metabolism , Pancreatitis/pathology , Pancreatitis/prevention & control , Protein Kinase C-delta/metabolism , Protein Kinase C-epsilon/metabolism , Protein Transport , Rats , Rats, Wistar , Restraint, Physical , Severity of Illness Index , Tissue Culture Techniques , Trypsin/metabolism , Tumor Necrosis Factor-alpha/immunologyABSTRACT
Pancreatic cancer is an aggressive malignancy with proclivity to early metastasis. High expression and activation of the collagenase matrix metalloproteinase-2 (MMP-2) have been found in human pancreatic cancer tissues, being these increased levels of active MMP-2 correlated to tumor invasion and metastasis. Hypoxia and reoxygenation (H-R) are critical pathophysiological conditions during ischemia-reperfusion injury, which has been shown to enhance both invasion and metastasis. In the present study, we investigated the effects of H-R on MMP-2 levels and the invasiveness properties of human pancreatic cancer cells PANC-1. Using specific inhibitors, we found that H-R treatment of these tumor cells induced secretion and activation of MMP-2, which was required for H-R-stimulated basement membrane degradation and cell invasion. Our results also indicate that signaling events involved in H-R-enhanced PANC-1 invasiveness comprehend PI3K-dependent activation of Rac1, which mediated the formation of NADPH-generated reactive oxygen species responsible for MMP-2 secretion and activation.
