Figure 6. Functional inhibition of CFTR reverses VX809-induced expression of Nrf2 target genes.

NhBE and CFhBE cells were treated with DMSO control, 1–10 μM VX809, or 30 nM CDDO, a Nrf2 activator, with or without 20 μM CFTR_inh-172 for 48 or 72 hours. Gene expression of Nrf2-activated genes, GCLC (A), HMOX1 (B), and NQO1 (C), was determined by real-time qPCR. Gene expression is expressed as fold changes versus control cells (DMSO control or CFTR_inh-172 alone), and was calculated from cycle threshold and normalization to the control gene, 18S rRNA. For 48-hour experiments (3 independent experiments from 3 patient donors each for non-CF and CF cells) and 72-hour experiments (7 independent experiments from 4 CF and 4 non-CF donors with 3 replicates per treatment per donor) and for 72-hour CDDO experiments (3 independent experiments from 4 CF and 4 non-CF donors with 3 replicates per treatment per donor), data are expressed as box-and-whisker plots. Horizontal bars indicate the median, box borders indicate 25th and 75th percentiles, and whiskers indicate 5th and 95th percentiles. *P < 0.05, **P < 0.01, ***P < 0.001 by mixed-effects ANOVA with Dunnett’s multiple-comparisons test.