Inhibitor experiments—cell culture

For assessing the effect of inhibition of p38MAPK signaling, cells were treated for 7 days with 5 μm SB203580⁴⁵ (EMD-Millipore, Billerica, MA, USA) dissolved in water. For assessing the combined effect of p38MAPK inhibition and the AR antagonist Enzalutamide^{27, 46} (SelleckChem, Houston, TX, USA) or the chemotherapeutic Docetaxel²⁸ (LC Laboratories, Woburn, MA, USA), cells were co-treated with SB203580 and either Enzalutamide/Docetaxel for 7 days. It is important to note that the concentration of SB203580 used to treat PCa cells in our experiments, results in selective inhibition of p38MAPK signaling, as also suggested in the study by Davies et al.⁴⁵ We did not observe any appreciable changes in the phosphorylation of Akt1, another potential target (data not shown).