Fig. 5

Regulation of protein phosphorylation of STAT3, AKT, the MAPKs ERK/JNK/p38 and their influence on downstream targets. a The STAT3, b AKT, c ERK/JNK/p38 protein phosphorylation was evaluated by immunoblotting under control conditions (ctrl) and in the presence of 0.5 µM and 1.5 µM acetylshikonin (AS), shikonin (S), and cyclopropylshikonin (CS) for 1 h in SW-1353 and Cal78 cells. Δ, represents the ratio of phosphorylated to unphosphorylated proteins (mean ± SD, n = 3). β-actin was additionally used as loading control. d Relative gene expression of the downstream targets cyclin D1, cMyc, SOCS3, and Sox9 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