Fig 2: GPX4 variants associated with increased GPx4 enzyme content but decreased activity in human atrial myocardium. Two distinct polymorphisms associated with increased tissue levels of GPx4 protein (A) but decreased GPx4 activity (B) are shown in the panels above. Each open circle represents one patient, open bars = Homozygous for the Referent nucleotide, hatched bars = Heterozygous for the variant nucleotide (i.e., one allele), filled bars = Homozygous for the variant nucleotide. **** p < 0.0001, *** p < 0.001, ** p < 0.01 for main effect between genotypes indicated.

Fig 3: Relationship between GPx4 enzyme content and activity in human atrial myocardium. GPx4 enzyme activity (μmol·min−1·g−1 total protein) and total GPx4 enzyme (mg) were measured in fresh lysates prepared from samples of human atrial myocardium using protocols described in Methods section. Both enzyme activity and enzyme concentration values shown here are normalized against the total tissue protein (g). Each symbol corresponds to one individual patient (N = 189 patients). Statistical significance was calculated using simple linear regression, with dashed lines showing 95% confidence intervals.

Fig 4: GPX4 promotes tumor progression and chemotherapy resistance in NPC by activating TAK1-JNK and IKK/NF-κB.A. The TAK1-NFκB/MAPK signaling pathway was examined in EBV-negative and EBV-positive NPC cells by immunoblotting. B Protein expression of TAK1 in EBV-negative and EBV-positive CNE2 cells transduced with siRNAs against endogenous TAK1. CCK-8 assay (C) and colony formation assay (D) in the indicated cells (n = 3). E. Dose–response curve for DPP, 5-FU, and TAX treatment in the indicated cells. F The TAK1-NFκB/MAPK signaling pathway was examined in the indicated stable cell lines treated with TAK1 siRNA by immunoblotting. G CCK-8 assay of CNE2 EBV-negative cells with stable overexpression of GPX4 treated with TAK1 siRNA (n = 4). H, I. Cell cycle analysis of the indicated cells by flow cytometry. J Colony formation of the indicated cells (n = 3). si Ctrl, negative control. Data are shown as the mean ± SD. **p < 0.01; ***p < 0.001; ****p < 0.0001. C, D and G, two-tailed unpaired t test.

Fig 5: GPX4 promotes cancer cell proliferation and tumorigenicity in vitro and in vivo.A CCK-8 assay of EBV-positive CNE2 (left) and HK1 (right) GPX4 knockdown cells. B Colony formation by the indicated cells (n = 3). C–E. Subcutaneous tumors formed by EBV-positive control and shGPX4 CNE2 cells in nude mice were excised 17 days after inoculation. Tumor growth was assessed by assessing volume changes over time (D) and weight at the endpoint (E) (n = 7). F Expression of GPX4 and Ki67 in the xenografts was examined by immunohistochemistry staining. G Cell death in the xenograft tumors was assessed by TUNEL staining (red). Data are shown as the mean ± SD. **p < 0.01; ***p < 0.001. A and B two-tailed unpaired t test. D and E two-tailed Mann–Whitney test. F and G scale bars: 100 µm (F) and 50 µm (G).