CCT245737 is a potent inhibitor of checkpoint kinase 1 (Chk1; IC50 = 1.3 nM).1 It is selective for Chk1 over Chk2 (IC50 = 2,440 nM). CCT245737 inhibits G2 checkpoint arrest induced by etoposide (Item No. 12092) in HT-29 colon cancer cells (IC50 = 30 nM). In vivo, CCT245737 (300 mg/kg) inhibits Chk1 autophosphorylation induced by gemcitabine (Item No. 11690) in an SW620 colon cancer mouse xenograft model. It reduces tumor volume when administered alone or in combination with gemcitabine in an HT-29 mouse xenograft model. CCT245737 (150 mg/kg) reduces inguinal, brachial/axillary, and mesenteric lymph node weights in the Eμ-Myc driven transgenic mouse transplant model of lymph gland-infiltrating B cell lymphoma.2WARNING This product is not for human or veterinary use.