Fig. 4

Triptonide promotes Twist1 degradation in TNBC cells through the lysosomal system. MDA-MB-231 and MDA-MB-468 cells were first incubated with 10 nM triptonide (TN) for 24 h, followed by incubation with the translational elongation inhibitor cycloheximide (CHX) at the concentration of 20 μM. After CHX treatment for 0 h, 4 h, 8 h, and 12 h, respectively, Twist1 protein levels were measured using Western blotting (A, C), and the bands were scanned and statistically analyzed (B, D). Twist1 protein levels were sharply decreased in MDA-MB-231 (E) and MDA-MB-468 cells (F) in the presence of TN, suggesting that triptonide triggers Twist1 protein degradation in the cells. Additionally, 20 μM chloroquine significantly inhibited triptonide-induced Twist1 protein degradation in MDA-MB-231 (G, H) and MDA-MB-468 cells (I, J). The results represent three independent experiments. *P < 0.05, **P < 0.01