p38 50 nM (IC 50 ) p38β2 500 nM (IC 50 )

SB203580 (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. Animal Model: Six-week-old female atymic Nu/Nu mice CAL27 p38WT and p38TM tumors Dosage: 5 mg/kg/day Administration: Intra peritoneal injected daily for 16 consecutive days Result: After 2 weeks treatment, CAL27 p38WT tumors were significantly smaller; CAL27 p38TM tumors were not affected by the p38 inhibitor (n=10).

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 IC 50 of 3-5 μM. SB203580 blocks PKB phosphorylation (IC 50 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. Cell Proliferation Assay Cell Line: CT6, BA/F3 cell line F7, and PBMC/T cells Concentration: 0-30 μM Incubation Time: Preincubated with 0-30 μM SB203580 for 1 h and cultured for 24 h in the presence of 20 ng/mL IL-2 Result: Prevented the IL-2-induced proliferation of primary human T cells, murine CT6 T cells, or BAF F7 B cells with an IC 50 of 3-5 μM. Western Blot Analysis Cell Line: CT6 cells, activated human T cells, and BA/F3 F7 cells Concentration: 0-30 μM Incubation Time: Preincubated with 0-30 μM SB203580 for 1 h before stimulating with 20 ng/mL IL-2 for 5 min Result: Inhibited the phosphorylation of PKB at Ser473 in a dose-dependent manner.

SB 203580 hydrochloride (RWJ 64809 hydrochloride) 是一种选择性的，ATP 竞争性的 p38 MAPK 抑制剂，对 SAPK2a/p38 和 SAPK2b/p38β2 的 IC50 分别为 50 nM 和 500 nM。SB 203580 hydrochloride 抑制 LCK，GSK3β 和 PKBα，IC50 比 SAPK2a/p38 高 100-500 倍。SB 203580 hydrochloride 是一种自噬 (autophagy) 和有丝分裂 (mitophagy) 激活剂。