Modulation of NRF2 by ATFs affects the sensitivity of normal and malignant ovarian epithelial cells against non‐cytotoxic and cytotoxic levels of ROS. OSE‐C2 and A2780 cells were transduced to express NRF2‐ATFs and were exposed to either non‐cytotoxic (≤10 μM N4Py, 200 μM H2O2) or cytotoxic (30 μM N4Py) levels of ROS. The effect on ROS production compared to 0.1% DMSO control treatment was determined after a 24 h exposure to 30 μM N4Py in OSE‐C2 (A) and 10 μM or 30 μM N4Py in A2780 (B) cells. (C) For a direct comparison between both cell lines, the absolute ROS production in OSE‐C2 and A2780 cells was determined after a 24h treatment with 30 μM N4Py. (D) OSE‐C2 cells were exposed to either a bolus of 200 μM H2O2, 5 μM N4Py or no treatment. After 2 days, metabolic activity was measured by MTS and compared to no treatment of the same cell line. (E) OSE‐C2 and A2780 cells were treated for 24h with 30 μM N4Py and the percentage of late apoptotic/necrotic cells (PI positivity) was determined by FACS analysis. Each value shows the mean ± SEM of at least three independent experiments. *p < 0.05, ***p < 0.001.