*3.1. Cytotoxicity of dec-RVKR-cmk in Vero Cells*

First, we examined the cytotoxicity of dec-RVKR-cmk in Vero cells by using luminescence-based cell viability assay. Viable cells were determined on the basis of ATP quantification of cells, which indicates the presence of metabolically active cells. Different concentrations of dec-RVKR-cmk were used against Vero cells and the results revealed that up to a 100 μM concentration dec-RVKR-cmk exhibited no cytotoxic effect, while 500 and 1000 μM concentrations were significantly toxic to cells (Figure 1b). The CC50 of dec-RVKR-cmk, which is the concentration that results in 50% cell viability, was determined to be 712.9 μM (log CC50 = 2.853) (Figure 1c).

**Figure 1.** Determination of cytotoxicity of dec-Arg-Val-Lys-Arg-cmk on Vero cells. (**a**) Chemical structure of dec-RVKR-cmk. (**b**) Cytotoxicity of dec-RVKR-cmk on Vero cells determined by CellTiter-GLO One Solution Assay kit (Promega). (**c**) The CC50 value was calculated from GraphPad Prism using non-linear regression analysis. Data are presented as mean ± SEM from three independent experiments.
