FIG 2.

Enhanced mitomycin C toxicity is dependent on the activity of Nrf2. (A) Viabilities of monococultured WT-GFP and Keap1 KO-mCherry cells, determined by total protein content relative to the DMSO control, exposed to the indicated concentrations of mitomycin C for 4 days. (B) Visualization of the cocultured WT-GFP and Keap1 KO-mCherry cells shows that in response to DMSO, the coculture is dominated by mCherry-expressing cells, while in mitomycin C-treated cells, the mCherry signal is significantly diminished, and the GFP-expressing cells expand their domain to fill the entire surface of the microplate well. Scale bars, 300 μm. (C) Fluorescence intensity of WT-GFP cells exposed to 0.1% DMSO or 50 nM mitomycin C, measured each day over a period of 6 days. (D) Fluorescence intensity of Keap1 KO-mCherry cells exposed to 0.1% DMSO or 50 nM mitomycin C, measured each day over a period of 6 days. The decrease in survival in response to mitomycin C is statistically significant from day 3. *, P < 0.001. (E) Fluorescence intensity of Keap1-Nrf2 DKO-mCherry cells exposed to 0.1% DMSO or 50 nM mitomycin C, measured each day over a period of 6 days. Note that the loss of Nrf2 completely rescues the phenotype. (F) Viabilities of cocultured WT-GFP and Keap1 KO-mCherry cells, determined by fluorescence intensity, exposed to 0.1% DMSO or 25 nM, 50 nM, or 100 nM mitomycin C, measured each day over a period of 7 days. The decrease in Keap1-mCherry cell survival is statistically significant for all mitomycin C concentrations from day 4. *, P < 0.001. (G) Viabilities of cocultured WT-GFP and Keap1-Nrf2 DKO-mCherry cells, determined by fluorescence intensity, exposed to 0.1% DMSO or 25 nM, 50 nM, or 100 nM mitomycin C, measured each day over a period of 7 days.