Fig. 3

Effect of sirt1 knockdown on tumorigenesis and radiosensitivity of breast cancer cells. MCF-7 and MDA-MB-231 cells were transfected with si-sirt1 or si-NC and cultured for 48 h. Cell viability was detected by CCK-8 assay in transfected MCF-7 (a) and MDA-MB-231 (b) cells. Apoptosis was evaluated by flow cytometry analysis in transfected MCF-7 (c) and MDA-MB-231 (d) cells. Colony formation assay was used to detect survival fraction in transfected MCF-7 (e) and MDA-MB-231 (f) cells exposed to 0, 2, 4, 6, or 8 Gy of irradiation. The expression of γ-H2AX in transfected MCF-7 (g) and MDA-MB-231 (h) cells with 6 Gy radiation was detected by γ-H2AX foci formation assay. *P < 0.05