Effects of squamocin on apoptosis. Cells were treated with 15, 30, and 60 μM squamocin for 24 h. Proteins were extracted and analyzed by Western blotting. GAPDH was used as a loading control. Squamocin enhanced caspase-3, -8, and -9 activities, cleaved the functional protein of PARP, increased phosphorylation levels of ERK, and decreased phosphorylation levels of JNK. (A) GBM841 cells. (B) Huh-7 cells. (C) SW620 cells. Data are representative of three independent experiments.