SB 203580

A specific p38 MAPK inhibitor with IC50 of 0.6 uM; shows selectivity over JNK, p42 MAPK, p90 S6K, p70 S6K, PKA, etc.; suppresses the activation of MAPKAP kinase-2 and prevents the phosphorylation of HSP27 in response to interleukin-1, cellular stresses and bacterial endotoxin in vivo.(In Vitro):Adezmapimod (SB 203580) (preincubated with 0-30 μM for 1 h and cultured for 24 h in the presence of 20 ng/mL IL-2) prevents the IL-2-induced proliferation of primary human T cells, murine CT6 T cells, or BAF F7 B cells with an IC50 of 3-5 μM.SB203580 blocks PKB phosphorylation (IC50 3-5 μM). SB203580 inhibitsthe phosphorylation of Ser473 in a dose-dependent manner in both CT6 and activated human T cells and IL-2-responsive BA/F3 F7 B cells.(In Vivo):Adezmapimod (SB 203580) (5 mg/kg/day; intra peritoneal injected daily for 16 consecutive days, in female atymic Nu/Nu mice) treatment, p38WT tumors show a significantly smaller tumor burden when compared with p38TM tumors that were treated in parallel.