Fig. 3: ZFL induces ER stress via calcium release from the ER.

a Caki cells were pre-treated with 20 μM 2-aminoethoxydiphenyl borate (2-APB) and 20 μM dantrolene for 30 min and then treated with 2 μM ZFL for 2 h (upper panel) or 8 h (lower panel). b Caki cells were pre-treated with 4 μM ruthenium red for 30 min and then treated with 2 μM ZFL for 2 h (upper panel) or 8 h (lower panel). Cells were loaded with Fluo-4/AM fluorescent dye, and calcium levels were measured using flow cytometry. Western blotting was used to detect the protein levels of ATF4, CHOP, and actin. The values in (a, b) represent the mean ± SD of three independent samples; *p < 0.01 compared to control; #p < 0.01 compared to ZFL