Mitochondrial function in three different types of airway epithelial cells

<b>Background:</b> The presence of COPD increases the risk of lung cancer up to 4.5-fold. Oxidative stress is a major cause of COPD and may promote the development of lung cancer. Oxidative stress may drive/derive from the mitochondrial dysfunction. We therefore assessed mitochondrial function in epithelial cells at baseline and following oxidative stress. <b>Hypothesis:</b> We hypothesized that oxidative stress may differentially affect mitochondrial function in primary bronchial epithelial cells and cell lines. <b>Methods:</b> Normal primary human bronchial epithelial cells (NHBE), the bronchial epithelial cell line (BEAS-2B), and the adenocarcinoma alveolar epithelial cell line (A549) were treated with 100µM H₂O₂ or left untreated for 4 hours. Mitochondrial membrane potential (ΔΨ_m), mitochondrial ROS (mROS), and intracellular ROS were measured using MitoProbe^TM JC-1, MitoSOX^TM Red and DCFH-DA respectively, using flow cytometry. Mitochondrial activity was measured using MTT assays and cell proliferation measured using the BrdU assay. <b>Results:</b> At baseline, A549 cells had higher mROS than BEAS-2B (p&lt;0.05), NHBE had higher ΔΨ_m than A549 (p&lt;0.05) and NHBE had higher intracellular ROS than BEAS-2B (p&lt;0.05). BEAS2B cells had a significantly higher rate of proliferation compared to A549 (p&lt;0.05), which were significantly higher than NHBE (p&lt;0.05). H₂O₂ significantly increased mROS in BEAS-2B cells compared to control (p&lt;0.05), but not in NHBE or A549 cells. H₂O₂ (100mM) had minimal effect on ΔΨ_m, mitochondrial activity and intracellular ROS in all three cell types. <b>Conclusion:</b> Baseline mitochondrial function differs between cell types, as does the response to H₂O₂, with increased mROS and reduced ΔΨ_m found in the A549 cancer cells.