Fig. 3

The induction of iron regulatory genes by ATM inhibition is essential for protection against ferroptosis a Depletion of ATM upregulates the mRNA expression of FTH1, FTL, and FPN1. MDA-MB-231 cells were transfected with siNC or siATM for 48 h and the mRNA levels of indicated genes were determined by qRT-PCR. b ATM inhibitor Ku-55933 upregulated the mRNA expression of FTH1, FTL, and FPN1. MDA-MB-231 cells were treated with Ku-55933 for 48 h, and the mRNA levels of indicated genes were determined by qRT-PCR. c, d Inhibition of ATM by siRNA (c) or Ku-55933 (d) increased the level of FTH1 protein. Cell lysates from siATM (69 h) or Ku-55933 (48 h) were analyzed by Western blots with indicated antibodies. e, f FPN1 and FTH1 are essential for ferroptosis protection by ATM inhibition. Cells were transfected with indicated siRNA for 78 h, and incubated with DMSO or erastin (10 μM) for 18 h before determining the viability by CellTiter-Glo. (The data are shown from one representative experiment with three biological replicates, and the data were reproduced from at least two independent experiments; Student’s t-test; *p < 0.05; **p < 0.01) g FTH1 is essential for ferroptosis protection by ATM inhibition for longer time course. MDA-MB-231 cells were transfected with indicated siRNA for 72 h, and incubated with DMSO or erastin for 70 h. The cell death was monitored from time 0 to 70 h by CellTox-Green. All the data were normalized to DMSO control in each group (The data are shown from three biological replicates.)