Fig. 2

Induction of apoptotic key players. a Protein expression of survivin, XIAP, Noxa, and the DNA damage marker γH2AX. The apoptotic key players were evaluated by immunoblotting under control conditions (0) and after treatment with 0.5–10 µM acetylshikonin (AS), shikonin (S), and cyclopropylshikonin (CS). β-actin was used as loading control. Δ ratio, fold change normalized to non-treated controls (mean ± SD of n = 3). Full-length blots are presented in Supplementary Fig. S1. b Relative gene expression of survivin, the metastasis marker MMP2, and angiogenic marker VEGF after treatment with shikonin derivatives for 24 h in SW-1353 (light grey striped) and Cal78 (dark grey dotted) cells (mean ± SD, n = 6, measured in triplicates). Statistical significances are defined as follows: * p < 0.05; ** p < 0.01; *** p < 0.001