27-OHC reduces p53 activation. a Luciferase reporter assay in MCF7 cells demonstrates a decrease in p53 activity in the presence of 0.1 μM 27-OHC, 1 μM 27-OHC, or 2 nM Estradiol (E2) for 24 h. b No change in p53 activity was detected with the luciferase reporter assay in the ER-negative MDA-MB 231 cells treated with 0.1 μM or 1 μM 27-OHC for 24 h. c Luciferase reporter assay in MCF7 cells demonstrates that fulvestrant, an ER inhibitor, attenuates 27-OHC-induced p53 inactivity when treated with 1 μM 27-OHC and/or 5 μM of fulvestrant. Data are expressed as Mean ± SEM. *p < 0.05, **p < 0.01, ***p < 0.001 versus vehicle. ##p < 0.01 versus 27-OHC only. RLU Relative luciferase units