Figure 3

Activation of AMPK is involved in berberine-induced cytotoxicity in HepG2 cells . HepG2 cells were either left untreated or treated with described concentration of berberine (10, 25, 50, 100 and 200 μM) for 4 hours, or treated with 100 μM of berberine for described time (15′, 30′, 1 h, 2 h and 4 h), phospho- and total AMPKα/ACC were tested by western blots (A and B). HepG2 cells were pre-treated with the AMPK inhibitor compound C (10 μM) for 1 hour, followed by berberine (100 μM) stimulation, cells were further cultured for 48 hours before cell viability was tested (C). Scramble control RNAi or AMPKα RNAi transfected HepG2 cells were either left untreated or treated with berberine (100 μM), cells were further cultured for 48 hours before cell viability was tested (D), expressions of AMPKα and β-actin in those cells were also tested by western blot (D, upper). Above cells were also tested for cell apoptosis 24 hours after stimulation (E), expressions of cleaved-caspase-3 and β-actin were examined (F), the number of LC3-GFP puncta positive cells were also recorded (G). HepG2 cells were either left untreated or treated with AICAR (1 mM), phospho- and total AMPKα/ACC were tested by western blots 2 hours after stimulation (H), and cell viability was examined by MTT assay after 48 hours incubation (I). Experiments in this figure were repeated three times, and similar results were obtained. *p < 0.05 (C and D). **p < 0.05 vs. berberine-treated group (G and E). ^#p < 0.05 vs. Ctrl group (I).