Human LCL cultures GM18870 (G/G, wild-type p53), GM18871 (A/A, homozygous S47), and GM18872 (A/G, heterozygous child from GM18870 and GM18871 parents) were identified for genotype at rs1800371 using the 1000 Genomes Web site and were obtained from the Coriell Institute. These were grown in RPMI supplemented with 15% fetal bovine serum (FBS) and 1% 100 IU/mL penicillin/100 µg/mL streptomycin (pen/strep). The genotype of these lines was confirmed by DNA sequencing. H1299 p53-null human non-small-cell lung carcinoma cells containing a tetracycline regulatory element (H1299 T-Reg) were provided by Steven McMahon (Thomas Jefferson University). The tetracycline-inducible p53 plasmid (Plenti4/TO/V5-DEST) was subjected to site-directed mutagenesis to generate the S47 variant. H1299 T-Reg wild-type or S47 p53 cells were maintained at 37°C in Dulbecco's modified Eagle's medium (DMEM; Cellgro), 1% pen/strep (Cellgro, 30-002-CI), and 10% tetracycline approved FBS (Clontech, 631106). MEFs were obtained from 12.5-d-old Hupki mice and were cultured at 37°C in DMEM with 1% pen/step and 10% FBS (Gemini, 100–106). Etoposide (Sigma, E1383), CDDP (Acros Organics, 193760010), and carboplatin (Sigma, C2538) were used at the indicated concentrations. Doxycycline (BD Biosciences, 631311) was used at a concentration of 100 ng/mL. RSL3 (Aobious, Inc., AO1514), erastin (Sigma Aldrich, 571203-78-6), and Fer-1 (Sigma Aldrich, SML0583) were used at the concentrations indicated.