KU-0060648 is a potent and selective inhibitor of DNA-dependent protein kinase (DNA-PK), (IC50 = 8.6 nM). Displays 20-1000 fold selectivity for DNA-PK over other PIKKs and a panel of 60 kinases. Inhibits proliferation of MCF7 cells in vitro and delays growth of MCF7 xenografts in mice. Also enhances CRISPR-Cas9-mediated homology-directed repair (HDR) efficiency, and attenuates nonhomologous end-joining (NHEJ). MW: 582.71. Purity ≥98% by HPLC