Effects of a novel tyrosine kinase inhibitor in rheumatoid arthritis synovial fibroblasts.
OBJECTIVE
Biologicals have revolutionised the treatment of rheumatoid arthritis (RA). However, progressive joint destruction can still be observed in many patients and the search for novel molecular therapies targeting specific signalling pathways is ongoing. In the present study, we investigated the effects of GW282974, a novel compound directed against tyrosine kinase activity with respect to the potential suppression of inflammation and destruction.


METHODS
Synovial tissue specimens were obtained from RA patients undergoing surgical joint replacement. Rheumatoid arthritis synovial fibroblasts (RASFs) were stimulated with cytokines and GW282974 was added in different concentrations. Gene expression was checked by TaqMan PCR, using 18S as housekeeping gene. Protein analysis was quantified by ELISA. Cell growth and proliferation was measured using the "ViaLight" proliferation assay.


RESULTS
EGF had no effect on the gene expression profile of RASFs when used as single stimulatory agent. In combination with pro-inflammatory mediators however, EGF showed a synergistic effect. The expression of matrix metalloproteinases, inflammatory cytokines and cyclooxygenase-2 on mRNA levels was strongly increased, whereas the addition of GW282974 abrogated these effects in a dose-dependent manner. These data could be confirmed on protein/lipid levels analysing the supernatants of RASFs by ELISA. Similarly, cell growth and proliferation of RASFs were inhibited by GW282974 in a dose- and time-dependent manner. By contrast, no cytotoxic effects were seen within the concentrations used.


CONCLUSIONS
GW282974 appears to interfere with the inflammatory and the destructive pathways in RASFs and might therefore be used as novel therapeutic strategy for the treatment of RA.
Center of Experimental Rheumatology, University Hospital Zurich, Gloriastrasse 25, CH-8091 Zurich, Switzerland. Lars.Huber@usz.ch
L C
LC
Huber
P
P
Künzler
S H
SH
Boyce
B A
BA
Michel
R E
RE
Gay
B S
BS
Ink
S
S
Gay
D017209:Apoptosis / Q000187:drug effects; D001172:Arthritis, Rheumatoid / Q000473:pathology*; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D016207:Cytokines / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004815:Epidermal Growth Factor / Q000037:antagonists & inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000187:drug effects*; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D018836:Inflammation Mediators / Q000037:antagonists & inhibitors / Q000494:pharmacology; D000077341:Lapatinib; D061965:Matrix Metalloproteinase Inhibitors; D020782:Matrix Metalloproteinases / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D011799:Quinazolines / Q000494:pharmacology*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D013583:Synovial Membrane / Q000187:drug effects* / Q000473:pathology
D016207:Cytokines; D018836:Inflammation Mediators; D061965:Matrix Metalloproteinase Inhibitors; D047428:Protein Kinase Inhibitors; D011799:Quinazolines; D000077341:Lapatinib; D004815:Epidermal Growth Factor; D020782:Matrix Metalloproteinases