Fig. 4.
A549 and BEAS-2B cells were treated with 1 µM B[a]P and incubated at the indicated pHe for 6, 24 and 48 h. CYP1A1 mRNA expression level was assessed in A549 cells (a) and BEAS-2B cells (b) by qRT-PCR. CYP1B1 mRNA expression level was assessed in A549 cells (c) and BEAS-2B cells (d) by qRT-PCR. All data were normalized with the house-keeping gene (β-actin) and compared to controls (A549 cells and BEAS-2B cells incubated with DMSO for 6 h) and expressed as mean ± SEM, n = 4; CYP450 s activity (CYP1A1 activity) was measured by an EROD assay in A549 cells (e) and BEAS-2B cells (f). Data are presented as relative fluorescence units/min (RFU/min) and expressed as mean ± SEM, n = 5. Statistical comparison was performed between each pH conditions (pH 7, 6.5 6 and 5.5) with pH 7.8 at each time point. *p < 0.05; **p < 0.01 and ***p < 0.001