Induction of cytotoxic DSBs by BMN673 and NL101. Representative images of γ-H2AX foci in control, NL101, BMN673 (BMN), and combination treated (COM) MV4-11 (a) and HL-60 (b) cells. (c) Quantification of γ-H2AX foci from immunofluorescent images shown in a and b (*P < .05, **P < .01, One-way ANOVA,combination treatments versus control and single treatments). (d) Western blot analysis of the DNA damage sensors ATM, p-ATM (Ser1981), CHK1, p-CHK1 (Ser317), CHK2 and p-CHK2 (Thr68) in MV4-11 and HL-60 cells. GAPDH served as a loading control.(e)Western blot analysis of PAR at different time points in MV4-11 and HL-60 cells. GAPDH served as a loading control.