Fig. 5: SiNPs impair lysosomal degradative capacity.

a A549 cells transiently expressing CFP-LC3 and YFP-LAMP1 were either starved or treated with SiNPs at 50 μg/mL for 12 h or 24 h. The cells were then fixed and imaged by confocal microscopy. The graph on the right shows the statistics of the colocalization coefficients of LC3-CFP and LAMP1-YFP. Scale bars: 5 μm. b A549 cells treated with 50 μg/mL of SiNPs for 24 h were pre-incubated with 100 ng/mL of EGF for 15 min, and then the EGF was removed. At the indicated time after EGF treatment, the cells were fixed and immunostained with anti-EGFR antibody. Scale bars: 10 μm. c Quantitative analysis of panel B was performed by normalization to the intensity of cells with EGF treatment for 1 h (n = 30). d The EGFR protein level from the cells treated as in (b) was detected by western blot. Data are presented as mean ± SEM, **P < 0.01