SB 218078 is an inhibitor of checkpoint kinase 1 (Chk1) that blocks phosphorylation of cdc25 with an IC50 value of 15 nM. It less potently inhibits cdc2 and PKC (IC50s = 250 and 1,000 nM, respectively) and causes 85% inhibition of PKD1 at 1 μM. SB 218078 releases G2 cell cycle arrest induced by γ-irradiation or the topoisomerase I inhibitor topotecan . In this way, SB 218078 enhances the cytotoxicity of DNA-damaging compounds.
SB 218078 is a selective inhibitor of Chk1.
ChEBI: LSM-1274 is an indolocarbazole.
Inhibitor of checkpoint kinase 1 (Chk1) that displays selectivity over other protein kinases (IC 50 values are 15, 250 and 1000 nM for Chk1, cdc2 and PKC respectively). Abrogates G 2 cell cycle arrest caused by γ -irradiation and topoisomerase I inhibition. Potentiates cytotoxicity of DNA-damaging drugs, enhancing the efficacy of some chemotherapeutics.
SB-218078 (2.5-5 μM; 18 hours; HeLa cells) treatment abrogates G2 cell cycle arrest caused by either γ-irradiation or a topoisomerase I Topotecan inhibition.SB-218078 (500-625 μM; 96 hours; HeLa and HT-29 cells) treatment significantly increases the cytotoxicity of DNA damage .
SB-218078 (5 mg/kg; intraperitoneal injection; for 16 hours; C57/Bl6 mice) treatment could promote a strong increase of γ-H2AX and apoptosis throughout the lymphoma, while having no effect on a healthy spleen in Myc-induced lymphomas mouse model.
15, 250 and 1000 nm for chk1, cdc2 and pkc respectively
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