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. Author manuscript; available in PMC: 2014 Dec 1.
Published in final edited form as: Nat Chem. 2014 May 11;6(6):504–510. doi: 10.1038/nchem.1944

Figure 4.

Figure 4

Neutral comet unwinding assay of K562 cells treated with (–)-lomaiviticin A (1), (–)-lomaiviticin C (2), or (–)-kinamycin C (3). (–)-Lomaiviticin A (1) induces DNA dsb formation in K562 cells at 0.5–50 nM concentrations, while 2 and 3 induce minimal production of DNA double-strand breaks (dsbs) at 300 nM concentrations. Tail moment obtained in a neutral comet unwinding assay employing 1 (0.5, 5.0, or 50 nM), 2 (300 nM), or 3 (300 nM) and K562 cells. Drug exposure was 30 min. Bars represent mean tail moment (60–140 cells), error bars represent standard error of the mean. IR = ionizing radiation. Tail moment represents the extent of DNA cleavage and is defined as the product of the tail length and the fraction of DNA in the tail. The neutral comet assay is a method for the selective detection of DNA dsbs in tissue culture (see ref. 34).