NQO1-Fluc reporter enzyme activity was determined by luminometry (n = 9) as previously reported [27 (link), 32 (link)]. Briefly, cells were lysed with passive lysis buffer for 10 min at 4 °C, and lysates were centrifuged for 15 min at 15,000 rpm at 4 °C. Aliquots of supernatant (20 μl) were mixed with 100 μl of luciferase assay reagent II (LARII, substrate for Fluc, Promega, Madison, WI) or coelenterazine (1 μg, substrate for Rluc in 100 μl PBS, Nanolight Technology, Pinetop, AZ) and analyzed using a luminometer (Turner Designs 20/20n, Sunnyvale, CA) to measure total light emission. This enabled quantification of both Fluc and Rluc activity in relative light units (RLU). Data were corrected for background signal, using lysates from untransfected cells, and normalized to protein content.