BACKGROUND: Graves' ophthalmopathy (GO) remains hard to treat. Excessive orbital fibroblast activation by platelet-derived growth factor (PDGF)-BB contributes to GO. The tyrosine kinase inhibitors (TKIs) imatinib mesylate and dasatinib both target PDGF-receptor tyrosine kinase activity, albeit with a different potency. We compared the efficacy of these TKIs on PDGF-BB-induced proliferation, and on cytokine and hyaluronan production by orbital fibroblasts. Also the capacity of dasatinib to suppress GO-associated gene expression in orbital tissue was examined.
METHODS: Orbital fibroblasts from four GO patients and five control subjects were used. The efficacy of the two TKIs was tested by: 1) pre-incubating orbital fibroblasts overnight with different TKI concentrations, followed by 24 h stimulation with PDGF-BB, 2) adding TKI and PDGF-BB simultaneously to the orbital fibroblasts in 24 h cultures. Proliferation was assessed by colorimetric assay. Hyaluronan and cytokine production were measured by ELISA. Furthermore, orbital tissue was obtained from a patient with active GO, and the effect of dasatinib on the expression levels of HAS2-, CCL2-, IL6-, and IL8-mRNA expression was examined by real-time quantitative PCR.
RESULTS: Pre-incubation of orbital fibroblasts with imatinib mesylate or dasatinib resulted in significant and dose-dependent inhibition of PDGF-BB-induced orbital fibroblast proliferation, and hyaluronan and cytokine production. Dasatinib exhibited these effects at far lower concentrations. The same results were observed in the setting where TKI and PDGF-BB treatments were commenced simultaneously. In orbital tissue from active GO, dasatinib significantly suppressed HAS2-, CCL2-, IL6- and IL8-mRNA levels.
CONCLUSION: Dasatinib may be a promising alternative to high-dose steroids in the treatment of GO.
|Number of pages||9|
|Journal||Graefe's archive for clinical and experimental ophthalmology = Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie|
|Publication status||Published - Jul 2014|
- Cell Proliferation/drug effects
- Cells, Cultured
- Chemokine CCL2/genetics
- Dose-Response Relationship, Drug
- Fibroblasts/drug effects
- Gene Expression Regulation/physiology
- Graves Ophthalmopathy/drug therapy
- Hyaluronan Synthases
- Imatinib Mesylate
- Protein Kinase Inhibitors/pharmacology
- Protein-Tyrosine Kinases/antagonists & inhibitors
- Proto-Oncogene Proteins c-sis/antagonists & inhibitors
- RNA, Messenger/genetics