CHEMBL5731764

BEAS-2B NQO1 MTT Assay: NAD(P)H:quinone oxidoreductase 1 (NQO1), also called DT diaphorase, is a homodimeric FAD-containing enzyme that catalyzes obligatory NAD(P)H-dependent two-electron reductions of quinones and protects cells against the toxic and neoplastic effects of free radicals and reactive oxygen species arising from one-electron reductions. The transcription of NQO1 is finely regulated by Nrf2, and thus NQO1 activity is a good marker for Nrf2 activation. On day one, frozen BEAS-2B cells (ATCC) are thawed in a water bath, counted, and re-suspended at a concentration of 250,000 cells/mL. Fifty microliters of cells are plated in 384 well black clear-bottomed plates. Plates are incubated at 37° C., 5% CO2 overnight. On day two, plates are centrifuged and 50 nL of compound or controls are added to the cells. Plates are then incubated at 37° C., 5% CO2 for 48 h. On day four, medium is aspirated from the plate and crude cell lysates are made by adding 13 μL of 1× Cell Signaling Technologies lysis buffer with 1 Complete, Mini, EDTA-free Protease Inhibitor Tablet (Roche) for each 10 mL of lysis buffer. After lysis plates are incubated for 20 min at room temperature. Two microliters of lysate are removed for use in Cell Titer Glo assay (Promega) and MTT cocktail is prepared (Prochaska et. al. 1998) for measurement of NQO1 activity. Fifty microliters of MTT cocktail is added to each well, plate is centrifuged, and analyzed on an Envision plate reader (Perkin Elmer) using Absorbance 570 nm label for 30 min. Product formation is measured kinetically and the pEC50 of NQO1 specific activity induction is calculated by plotting the change in absorbance (Delta OD/min) versus the log of compound concentration followed by 3-parameter fitting.