Fig. 2

miR-26a-5p upregulation promotes the sensitivity of Cisplatin and DNA damage in TNBC cell lines. A, B Cisplatin-insensitive (MDA-MB-231) and Cisplatin-sensitive (BT549) TNBC cell lines were chosen to transfect miR-26a-5p mimics and normal control. Different concentrations of Cisplatin were diluted with medium containing 1% FBS to incubate cell lines for 72 h. CCK8 was used to detect cytotoxicity. C–E Comet assay was used to identify the level of DNA damage after Cisplatin treatment to MDA-MB-231 and BT549 cells overexpressing miR-26a-5p, respectively, in 20 µM and 2 µM. F CCK8 was used to detect the live cell count at different time points after a special concentration of Cisplatin treatment (MDA-MB-231, 20 µM and BT549, 2 µM). G Western blot was used to measure the expression of DNA damage mark, γH2AX, in MDA-MB-231 and BT549 cells overexpressing miR-26a-5p at different time points after Cisplatin treatment. H, I Immunofluorescence was adopted to detect γH2AX expression change in the MDA-MB-231 cells exposed to Cisplatin for 6 h. **P < 0.01, ***P < 0.001, ****P < 0.0001 vs. control. N.S. not significant. n = 3