Figure 2. Correlation between oxidative stress-mediated reduction in SIRT1 and increased miR-34a expression.

BEAS2B cells were stimulated for 48 hours with H₂O₂ at concentrations of 25, 50, 75, 100 and 150 μM, and protein or RNA extracted. (A) RNA was extracted to examine miR-34a (n = 6) (B) and SIRT1 (n = 6). (C) Protein was extracted and SIRT1 protein expression was determined by SDS-PAGE/Western blotting normalized to β-actin (n = 5). BEAS2B cells were stimulated for 4, 8, 24 and 48 hours with 100 μM H₂O₂ and protein and RNA extracted, (D) changes in miR-34a expression was examined (n = 5), as well as changes in (E, F) SIRT1 gene and protein expression (n = 5). The band density of each blot is represented as a histogram and and is the average of all experiments performed. Data are means ± SEM, analyzed by Kruskal–Wallis test with post hoc Dunns and One-way Anova with post hoc Bonferroni *P < 0.05, **P < 0.01, ***P < 0.001.