Figure 4

Co-administration of olaparib and AZD1775 had a synergistic, anti-proliferative effect on TNBC cells. (a) Sub-G1 population after co-treatment. MDA-MB-231 and Hs 578 T cells were treated with AD1775 at 250 nmol/L and/or olaparib at 2.5 μmol/L for 5 d, sub-G1 populations were investigated by flow cytometry. Bars represent ±SDs (n = 3). ***P < 0.001. (b) Increased sensitivity to olaparib by AZD1775. Cellular DNA contents were measured by flow cytometry after PI staining. Sub-G1 proportions are shown in the bar graph. Bars represent ±SDs (n = 3). ***P < 0.001. (c) Co-treatment with AZD1775 and olaparib increased damaged DNA accumulation as compared with treatment with either agent alone. MDA-MB-231 and Hs 578 T cells were treated with AD1775 at 250 nmol/L and/or olaparib at 2.5 μmol/L for 5 d. The scale bars indicate 200 μm. Data presented are the mean tail length ±SD from a single representative experiment. *P < 0.05, **P < 0.01. (one-way ANOVA: Duncan’s post-hoc Test). (d) AZD1775 inhibited the formation of RAD51 foci caused by olaparib. Blue indicates DAPI staining, representing DNA, green indicates γ-H2AX, representing the degree of DNA damage, and RAD51, which was used to confirm HR capacity, is indicated by red. The scale bar indicates 20 µm. 100 cells were counted per group in a treatment. Bars represent ±SDs (n = 3).