Abstract
Stimulation of hepatic stellate cells (HSCs) by platelet-derived growth factor (PDGF) and transforming growth factor-beta1 (TGF-beta1) is an essential pathway of proliferation and fibrogenesis, respectively, in liver fibrosis. We provide evidence that PTK787/ZK222584 (PTK/ZK), a potent tyrosine kinase inhibitor that blocks vascular endothelial growth factor receptor (VEGFR), significantly inhibits PDGF receptor expression, as well as PDGF-simulated HSC proliferation, migration and phosphorylation of ERK1/2, Akt and p70S6 kinase. Interestingly, PTK/ZK also antagonizes the TGF-beta1-induced expression of VEGF and VEGFR1. Furthermore, PTK/ZK downregulates TGF-beta receptor expression, which is associated with reduced Akt, ERK and p38MAPK phosphorylation. Furthermore, PDGF-induced TGF-beta1 expression is inhibited by PTK/ZK. These findings provide evidence that PTK/ZK targets multiple essential pathways of stellate cell activation that provoke proliferation and fibrogenesis. Our study underscores the potential use of PTK/ZK as an antifibrotic drug in chronic liver disease.
Publication types
-
Research Support, N.I.H., Extramural
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Animals
-
Cell Movement / drug effects
-
Cell Proliferation / drug effects
-
Cells, Cultured
-
Down-Regulation / drug effects
-
Enzyme Activation / drug effects
-
Extracellular Signal-Regulated MAP Kinases / metabolism
-
Hepatic Stellate Cells / drug effects*
-
Hepatic Stellate Cells / metabolism
-
Liver Cirrhosis / drug therapy
-
Phthalazines / pharmacology*
-
Phthalazines / therapeutic use
-
Platelet-Derived Growth Factor / metabolism*
-
Protein Kinase Inhibitors / pharmacology*
-
Protein Kinase Inhibitors / therapeutic use
-
Proto-Oncogene Proteins c-akt / metabolism
-
Pyridines / pharmacology*
-
Pyridines / therapeutic use
-
RNA, Messenger / metabolism
-
Rats
-
Receptor, Platelet-Derived Growth Factor beta / metabolism
-
Receptors, Transforming Growth Factor beta / metabolism
-
Ribosomal Protein S6 Kinases, 70-kDa / metabolism
-
Signal Transduction / drug effects
-
Smad2 Protein / metabolism
-
Transforming Growth Factor beta1 / metabolism*
-
Vascular Endothelial Growth Factor A / metabolism
-
Vascular Endothelial Growth Factor Receptor-1 / metabolism
-
p38 Mitogen-Activated Protein Kinases / metabolism
-
raf Kinases / metabolism
Substances
-
Phthalazines
-
Platelet-Derived Growth Factor
-
Protein Kinase Inhibitors
-
Pyridines
-
RNA, Messenger
-
Receptors, Transforming Growth Factor beta
-
Smad2 Protein
-
Smad2 protein, rat
-
Transforming Growth Factor beta1
-
Vascular Endothelial Growth Factor A
-
vatalanib
-
Flt1 protein, rat
-
Receptor, Platelet-Derived Growth Factor beta
-
Vascular Endothelial Growth Factor Receptor-1
-
Proto-Oncogene Proteins c-akt
-
Ribosomal Protein S6 Kinases, 70-kDa
-
raf Kinases
-
Extracellular Signal-Regulated MAP Kinases
-
p38 Mitogen-Activated Protein Kinases