DNA-PK-IN-8 is a highly potent, selective and orally active DNA-dependent protein kinase ( DNA-PK ) inhibitor with an IC 50 value of 0.8 nM. DNA-PK-IN-8 exhibits synergistic antiproliferative activity against a series of cancer cell lines and significantly suppresses HL-60 tumor growth, when using in combination with Doxorubicin.