Figure 2 Application of latrunculin A on the “transformed” synovial fibroblast. Disruption of actin cytoskeleton was induced with 4 µg/ml latrunculin A (Sigma) for 2 h at 37°C as previously described.⁹² As control of TNFα involvement in the actin cytoskeleton organisation 1 μg/ml anti‐TNF (infliximab) was added on TgSFs for the same period of time. (A, B, D) Adhesion, migration and proliferation assays were performed as previously described.⁵⁶ (C) Apoptosis assays were performed by treating cells with 0.002–0.05 μM staurosporine, for 24 h at 37°C overnight. Cell survival was determined using the crystal violet assay as before.⁸ All results are expressed as the means±SE of one representative experiment performed in triplicate. Statistical analysis was performed using Student t test, with a level of significance set at p<0.05.