CHK1 inhibition also increased CPX-351-induced apoptosis in additional AML lines, including HL-60 (Fig. 4a), ML-2 (Fig. 4b and Supplementary Fig. S4a), THP.1 (Fig. 4c), and ML-1 cells (Supplementary Fig. S4b). Here, CHEK1 is linked to acute myeloid leukemia.