Pharmacological Inhibition of MAPK Pathways

When needed, samples were treated with 10 µM of MAPK-p38 specific inhibitor, SB203580 [4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)-1H-imidazole] (BioSource, LabClinics, Barcelona, Spain). Also, 20 µM of SP600125 [Anthra(1,9-cd)pyrazol-6(2H)-one] (Biosource, LabClinics), a pharmacological inhibitor of c-Jun NH2-terminal kinase (JNK), was used. These concentrations have been proven effective in a number of studies [78 (link),79 (link)]. The inhibitors were dissolved in dimethyl sulfoxide (DMSO; Sigma, Madrid, Spain). An equal dose of DMSO (vehicle) was added to the control dishes. The final DMSO concentration in the media was always ≤0.01%, which was proven not to influence the cell growth rate in the cultures (data not shown). On the third day after seeding (long-term proliferation assays) or on the fourth day after seeding (short-term assays), the medium was renewed and supplemented with the inhibitor or the vehicle 1 h prior to the MF- or sham-exposure onset.