Quantitative effect of rBC2LCN-PE38 on the cell viability of human induced pluripotent stem cells (hiPSCs). 201B7 hiPSCs, 253G1 hiPSCs, human dermal fibroblasts (hFibs), and human adipose-derived mesenchymal stem cells (hMSCs) were cultured with varying concentrations of rBC2LCN-PE38 or rBC2LCN-PE23. After 24 h, the medium was replaced with fresh medium supplemented with 20 μL of Cell Counting Kit (CCK)-8 solution, and the absorbance at 450 nm was measured after a further 4 h incubation. Viability (%) was calculated from the absorbance at 450 nm of treated cells relative to untreated cells. Data are shown as mean ± SD (for triplicate measurements). Median lethal dose (LC50) was calculated by GraphPad Prism7 software.