Figure 3
Effect of cigarette smoke extract (CSE) on the expression of hypoxia-inducible factor 1 (HIF-1)-dependent genes.
(a) A549 cells were cultured for 6 h with or without 2% CSE under 20% O2 or 1% O2 prior to analysis of vascular endothelial growth factor (VEGF), heme oxygenase-1 (HO-1), regulated in development and DNA damage response 1 (REDD1) and matrix metalloproteinase 9 (MMP-9) mRNA levels using real-time reverse transcriptase polymerase chain reaction (RT-PCR). Fold expression was calculated relative to untreated control cells. (b) A549 cells were transfected with small interfering RNA (siRNA) targeting HIF-1α (hif1a) or a negative control (scr) and exposed to CSE or 1% O2 for 6 h. HIF-1α, VEGF and REDD1 mRNAs were analyzed by RT-PCR and fold expression was calculated relative to untreated cells. (c,d) A549/5HRE-Luc cells (c) or A549/5HRE-Luc cells transfected with hif1a or scr siRNAs (d) were exposed to the indicated conditions for 8 h prior to analysis of luciferase activity. Fold activity was calculated relative to untreated cells and experiments were repeated at least three times in triplicate. Data are presented as the mean ± SD; *p < 0.05, as compared with control (no treatment); #p < 0.05 for the indicated comparisons.
