Fig. 1

CEP triggers the accumulation of autophagosomes in human cancer cells. a The chemical structure of CEP. b MDA-MB-231 and MCF-7 cells transfected with EGFP-LC3 were treated without or with CEP (4 μM) for 24 h, the EGFP-LC3 puncta were observed under confocal microscopy; scale bars: 10 μm. c Quantification of average EGFP puncta per cell in (b) from 3 independent experiments. Data was presented as mean ± SD (**P < 0.01 compared with control); 50 cells were analyzed per treatment condition. d and e Cells were treated with various concentrations of CEP for 24 h, or treated with CEP (4 μM) for different time intervals as indicated. Western blot analysis was employed to determine the expression of autophagy-related proteins (LC3B-I/LC3B-II and SQSTM1). The relative levels of LC3B-II and SQSTM1 were normalized to GAPDH in three independent experiments (mean ± SD, *P < 0.05 or **P < 0.01 compared with control). The ratio of LC3-II/LC3-I was quantified in three independent experiments (mean ± SD, *P < 0.05 or **P < 0.01 compared with control). f Various cancer cells were treated with CEP (4 μM) for 24 h as indicated. The expression of LC3B-I/LC3B-II and SQSTM1 was detected by western blot. GAPDH was used as a loading control