Fig. 2.

Effect of inhibitors of NADPH oxidase on PMA-induced responses. (A) NHBE cells were pretreated with DPI (1.0 μM) for 30 min and then exposed to PMA (10 ng/ml) for 30 min to measure H₂O₂ production. (B) NHBE cells were pretreated with an anti-EGFR-neutralizing Ab and with DPI (1.0 μM) for 30 min and then stimulated with PMA for 2 h to measure TGF-α in the supernatants. (C) NHBE cells were pretreated with DPI (1.0 μM), AP (100 μM), or NMEA (100 μM) for 30 min, then treated with PMA for 8 h to analyze MUC5AC gene expression or for 24 h to measure mucin protein production (D). Similar results were obtained in NCI-H292 cells (data not shown). Data are expressed as mean ± SD (n = 3). *, P < 0.01, compared with PMA alone.