JNK activation is required for the up-regulation of Beclin-1 and subsequent cell death by SSE. (A) After pre-incubation with specific inhibitors including SP600125 (10 μM), SB203580 (10 μM), PD98059 (10 μM), or 3-MA (100 μM) for 1 h, B16F10 cells were treated with SSE at 50 μg/mL for 24 h and then observed under phase contrast microscope. (B) The effect of specific MAPK inhibitors on the expression of Beclin-1, LC3-I/-II, Bcl-2, and Bax was evaluated. Cell lysates were prepared after incubation for 12 h with specific inhibitors for 1 h before SSE treatment. (C) After pre-incubation with or without specific inhibitors, cells were treated with 50 μg/mL SSE for 24 h, and cell viability was determined using MTT assay. Data acquired from 2 independent experiments are expressed as mean ± SD. *p < 0.05 versus control, **p < 0.05 versus SSE-treated cells.