Figure 3

Inhibition of autophagy mitigates ZnONPs-induced cell death. (a) A549 cells were pretreated with 3-MA (5 mM), followed by treatment with 30 or 50 μg/ml ZnONPs. MTS analysis of A549 cells was performed at 24 h after ZnONPs treatment. Data are representative of three independent experiments (n=6 for each group) and values are expressed as mean±S.E.M. **P<0.01. (b) Western blot analysis of LC3 and p62 expression levels in A549 cells treated with 3-MA (5 mM), followed by treatment with 30 μg/ml ZnONPs at an indicated time. β-Actin served as a loading control. Images are representative of three independent experiments. (c) A549 cells were treated with 3-MA (5 mM), followed by treatment with 30 μg/ml ZnONPs. FACS analysis of cells stained with FluoZin-3, AM was performed at 24 h after treatment. Images are representative of three independent experiments. (d) A549 cells were transfected with 75 nM control siRNA (si-Ctrl) or specific Beclin-1 siRNA (si-Beclin-1) for 48 h. The efficiency of knockdown was detected by western blot analysis. β-Actin served as a loading control. Images are representative of three independent experiments (top panel). MTS analysis was then performed to detect the cell viability of si-Ctrl- or si-Beclin-1-treated cells at 24 h after treatment with 30 μg/ml ZnONPs. Data are representative of three independent experiments (n=6 for each group) and values are expressed as mean±S.E.M. **P<0.01 (bottom panel)