Fig. 3

MRE11:p.K464R mutation leads to Olaparib resistance in ovarian cancer cells. (A-B) The stable cell lines of SKOV3 (A) and A2780-MRE11^WT/MRE11^K464R (B) were constructed expressing MRE11^WT and MRE11^K464R protein and detected the MRE11 protein expression with Western blot. (C-D) SKOV3 (C) and A2780 (D) MRE11^WT /MRE11^K464R cells were treated for 96 h with indicated dose of Olaparib and viability assessed by CCK8. (E-F) Representative pictures of colony formation assay in SKOV3 (E) and A2780 (F) MRE11^WT /MRE11^K464R cells treated with or without Olaparib for 10 days are in left. Relative colony formation rates of cell are presented as percent relative to DMSO (right). (G-H) SKOV3 (G) and A2780 (H) MRE11^WT/MRE11^K464R cells were treated with or without Olaparib for 48 h and then stained for γH2AX, MRE11, and DAPI (left), and quantified the γH2AX foci per cell (right). Scale bar, 25 μm. (I-J) SKOV3 (I) and A2780 (J) MRE11^WT/ MRE11^K464R cells were treated with or without Olaparib for 48 h and subjected to Comet analysis. DNA damage is quantified as percent DNA in tails. Each group represents at least 100 cells counted. Data are presented as mean values ± SEM from three independent experiments. ***p < 0.001, ****p < 0.0001, ns, not significant, as determined by the unpaired two-tailed Student’s t-test