Characterization of DNA-PK and PARP-1 levels and activities in the cell lines studied. Characterization of DNA-PK and PARP-1 levels and activities in the cell lines studied. A, Western blot analysis of PARP-1 and DNA-PK. Blots were probed using antibodies against PARP-1 and DNA-PKcs; B, DNA-PK activity; C, PARP-1 activity. Results are the mean of three replicate samples each from three independent experiments ± SE. Stephany J. Veuger et al. Cancer Res 2003;63:6008-6015 ©2003 by American Association for Cancer Research