Fig. 2. Honeybee venom and melittin induce apoptosis and membrane disruption.

a Western blot for the detection of cleaved caspase-3 (CL-csp-3) in SUM159 cells treated with vehicle (1), honeybee venom (2–3), and melittin (4–5) for 18 and 24 h. b Flow cytometry analysis of SUM159 cells treated with the IC₅₀ of honeybee venom (5.58 ng/µL) and the IC₅₀ of melittin (4.24 ng/µL) for 1 h. c Cell-viability temporal response assays of normal human dermal fibroblasts (HDFa) and breast cancer cells (SUM159 and SKBR3) treated with honeybee venom (left) or melittin (right) over 1 hour (two-way ANOVAs). d Live-cell confocal microscopy of SKBR3 cells treated with the IC₅₀ of honeybee venom (5.77 ng/µL) over 1 h, with time in minutes post treatment. Scale bars represent 15 µm. e Scanning electron microscopy of SUM159 cells treated with the IC₅₀ of honeybee venom (5.58 ng/µL) and the IC₅₀ of melittin (4.24 ng/µL) over 1 h, with two representative images shown for each treatment group. The white outline in the top images indicates the respective regions of each cell in the bottom images. Scale bars represent 10 µm (top row) and 200 nm (bottom row). Data are represented as mean ± SEM (n = 3). Differences were considered significant at p < 0.05 (*), p < 0.01 (**), and p < 0.001 (***). See also Supplementary Figs. 2, 10, and 16.