Supplementary Figure 1: KS100 is a multi-ALDH inhibitor. Supplementary Figure 2: Conformational arrangements of ALDH1A1, 2, and 3A1 are structurally identical. Supplementary Figure 3: Representative dot plots of Aldered staining of UACC 903 cells following ALDH inhibitor treatment. Supplementary Figure 4: Representative dot plots of Aldered staining of 1205 Lu cells following ALDH inhibitor treatment. Supplementary Figure 5: KS100 reduces enzymatic ALDH activity in cell lysates. Supplementary Figure 6: Representative dot plots of Annexin-V-PE/7-AAD staining of UACC 903 cells following ALDH inhibitor treatment. Supplementary Figure 7: Representative dot plots of Annexin-V-PE/7-AAD staining of 1205 Lu cells following ALDH inhibitor treatment.</p