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. Author manuscript; available in PMC: 2011 Jul 1.
Published in final edited form as: Cytometry A. 2010 Jul;77(7):591–606. doi: 10.1002/cyto.a.20889

Figure 6.

Figure 6

Supravital assessment of DNA content. (A) Comparison between propidium iodide (PI), DRAQ5, and DyeCycle Orange (DCO) probes. Human histiocytic leukemia U937 cells were challenged with topoisomerase II inhibitor (Etoposide); topoisomerase I inhibitor (Camptothecin), or left untreated (Control). Cells were live stained with DRAQ5 and DCO for 20 minutes at RT. For PI staining cells were harvested, permeabilized in 70% EtOH, and digested with RNase A. Note that resolution of DNA profile when using DRAQ5 and DCO is satisfactory to assess cell cycle block in response to Etoposide and Camptothecin. Interestingly both DRAQ5 and DCO permit also for supravital assessment of sub-G1 fraction. (B) Comparison between DRAQ5 and ethidium bromide in a HTS screen of selected anticancer drugs. Note that permeabilisation and fixation result in loss of informative cells in the sub-G1 fraction (thick arrow). The same population is retained when DRAQ5 is applied supravitaly for DNA content analysis (data courtesy of Roy Edward, Biostatus Limited Shepshed, UK) (114—117). [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com]