CHEK1 and leukemia: V158411 treatment of leukemia and lymphoma cell lines induced Chk1 degradation that was proteasome dependent [38] whilst degradation of Chk1 was observed in HT29 cells following treatment with four structurally distinct Chk1 inhibitors in combination with gemcitabine: V158411, LY2603618, MK-8776 and GNE-900 [46].