B–FDose–response curves for cell viability after 48 h of NFR treatment measured using the MTS assay. Curves and bar graphs for EC50 are mean ± s.e.m. of three independent experiments performed in triplicate. For curves, P‐values were calculated using two‐way ANOVA. For the bar graphs, P‐values were calculated using two‐tailed unpaired Student's t‐tests (B, E), one‐way ANOVA with Bonferroni (C), or Dunnett's multiple comparison post‐tests (D and F). *P‐value ≤ 0.05, **P‐value ≤ 0.01, ***P‐value ≤ 0.001. (B, C) eEF2K−/− MEFs show a decreased susceptibly to NFR compared to eEF2K+/+ controls (B) whereas eEF2K reconstitution restores NFR sensitivity (C). (D‐F) HeLa (D), A549 (E), and MCF7 (F) clones with CRISPR/Cas9‐generated eEF2K deficiency (Cr‐eEF2K) show a decreased susceptibility to NFR compared to control cells (CrLuci).