Fig. 6. NRF2 expression correlates with HERC2 and VAMP8 levels in human cancer tissues, as well as ferroptosis resistance.

(A) Correlation between NRF2 expression and HERC2 or VAMP8 levels in human ovarian tissues was determined by immunohistochemistry analysis. HERC2, VAMP8, and SLC7A11 expression were imaged (see fig. S4A), and average intensity was measured and plotted against NRF2. Normal tissue (n = 10) plotted as red dots; cancer tissue (n = 40) plotted as black dots. (B) NRF2 and ferroptosis-related protein levels in various ovarian cancer cell lines were measured by immunoblot analysis (left). The expression of HERC2, VAMP8, and SLC7A11 was quantified and plotted against NRF2 in each cell line (right). (C) Correlation between NRF2 expression and the GI₅₀ of ferroptosis-inducing compounds (IKE, erastin, RSL3, SAS, l-glutamate, and FIN56) and apoptosis-inducing compounds (cisplatin, mitomycin C, or staurosporine). Each cell line was treated with eight doses of the indicated compound for 24 hours, and cell viability was measured by MTT assay. GI₅₀ values were calculated by log-logistic fitting (Table 3). (D) Heatmap GI₅₀ profiles were created using median-centered z-score analysis of the GI₅₀ values.