Figure 4
From: FOXM1 targets NBS1 to regulate DNA damage-induced senescence and epirubicin resistance
FOXM1 regulates NBS1 expression and ATM activity in MCF-7 and MCF7-EpiR cells. (a) MCF-7 and MCF7-EpiR cells were treated with 1 μM epirubicin for 0, 4, 8, 16, 24 and 48 h. Following treatment, the expression levels of FOXM1, NBS1, P-NBS1, RAD50, MRE11, P-ATM, ATM and β-tubulin were determined by western blotting. (b) Real-time quantitative PCR (qRT–PCR) was used to determine FOXM1 and NBS1 mRNA transcript levels (normalized against L19 mRNA levels). Bars represent the mean+s.d. of three independent experiments. (c, d) MCF-7 and MCF7EpiR cells were transfected with either NS siRNA or FOXM1 siRNA. Twenty-four hours after transfection, the cells were either untreated or treated with 1 μM epirubicin for 24 h. (c) The protein expression was determined by western blot analysis using antibodies against FOXM1, NBS1, P-NBS1, RAD50, MRE11, P-ATM, ATM, P-CHK2,CHK2 and β-tubulin. (d) FOXM1, NBS1, MRE11 and RAD50 transcripts were next analysed by qRT–PCR in the untreated cells (all gene transcripts were normalized against L19). Statistical significance was determined by Student’s t-test (**P⩽0.01, ***P⩽0.005, significant; n.s., non-significant).
