Tyrosine kinase activity of purified recombinant cytoplasmic domain of platelet-derived growth factor β-receptor (β-PDGFR) and discovery of a novel inhibitor of receptor tyrosine kinases

• Published in: Biochemical pharmacology 1999, Vol.57 (1), p.57-64
• Main Authors: Zaman, Guido J.R., Vink, Paul M.F., van den Doelen, Antoon A., Veeneman, Gerrit H., Theunissen, Henri J.M.
• Format: Article
• Language: English
• Subjects: 3T3 Cells; Animals; Becaplermin; Biological and medical sciences; Carcinoma, Squamous Cell; Cell Division - drug effects; Cell Line; Cell physiology; Cell receptors; Cell structures and functions; Cytoplasm - enzymology; Enzyme Inhibitors - pharmacology; Epidermal Growth Factor - pharmacology; Fibroblast Growth Factor 2 - pharmacology; fibroblast growth factor receptor; Fundamental and applied biological sciences. Psychology; growth factor receptor tyrosine kinase inhibitors; Growth Substances - pharmacology; Hormone receptors. Growth factor receptors. Cytokine receptors. Prostaglandin receptors; Humans; Indoles - pharmacology; Kinetics; Mice; Molecular and cellular biology; Muscle, Smooth, Vascular; Phosphorylation; Phosphotyrosine - metabolism; Platelet-Derived Growth Factor - pharmacology; platelet-derived growth factor receptor; Proto-Oncogene Proteins c-sis; Pulmonary Artery; Receptor Protein-Tyrosine Kinases - antagonists & inhibitors; Receptor Protein-Tyrosine Kinases - isolation & purification; Receptor Protein-Tyrosine Kinases - metabolism; Receptor, Platelet-Derived Growth Factor beta; Receptors, Platelet-Derived Growth Factor - genetics; Receptors, Platelet-Derived Growth Factor - isolation & purification; Receptors, Platelet-Derived Growth Factor - metabolism; Recombinant Proteins - isolation & purification; Recombinant Proteins - metabolism; Signal transduction; Transfection; Tumor Cells, Cultured; tyrosine kinase; vascular smooth muscle cells
• ISSN: 0006-2952; 1873-2968
• DOI: 10.1016/S0006-2952(98)00271-8

Aberrant expression of platelet-derived growth factor and its receptor (PDGFR) has been implicated in various human disorders, including cardiovascular disease and certain types of cancer. Inhibitors of the tyrosine kinase activity of PDGFR are leads in the development of novel agents to combat these diseases. We describe here a novel, potent inhibitor of PDGFR tyrosine kinase, 3-(4-dimethylamino-benzylidenyl)-2-indolinone (DMBI). The compound also inhibits signal transduction through fibroblast growth factor receptor 1 (FGFR1), but is not active towards epidermal growth factor receptor (EGFR) or c-Src tyrosine kinase. The activity of DMBI and other tyrosine kinase inhibitors was compared in a cell-based assay as well as in an assay based on purified recombinant platelet-derived growth factor β-receptor (β-PDGFR) lacking the transmembrane and ligand-binding domain. We showed that this truncated β-PDGFR could dimerize, and that dimerization was required for tyrosine kinase activity. Tyrosine kinase activity was modulated by inhibitors of β-PDGFR autophosphorylation in cells, but not by specific inhibitors of EGFR or c-Src tyrosine kinase. We conclude that β-PDGFR lacking the transmembrane and ligand-binding domain retains the essential properties of the full-length receptor tyrosine kinase.