Cellular viability of human skin cancer and normal human skin cell lines treated with RRM-designed peptides for 18 h measured by MTT assay. MM96L cells in (A), COLO-16 cells in (B), and HDF cells in (C) were treated with different concentrations of RRM-MV or RRM-C for 18 h. Cells from each cell line were treated with 90% DMSO and used as positive controls. The effect of the peptides on cell viability was determined by MTT assay. Results are reported as percentage of cell death, where the optical density (OD) value from untreated cells was set at 0% of cell death. Bars indicate the mean ± standard error of three independent experiments. Statistical evaluation was performed by using one-way ANOVA and Tukey post hoc test. The RRM-MV-treated cancer cells were significantly different from untreated cells (P < 0.001).