Figure 4.

The expressions of Snail and vimentin inhibited by propolin G via protein degradation pathway in MDA-MB-231 cells. MDA-MB-231 cells were stimulated with propolin G for 24 h after proteasome inhibitor (MG132, 5 μM) pretreatment for 1 h. Then, collected cell lysates were subjected to analysis of (A) the expression of Snail and vimentin by Western blot. The cell lysates were immuno-precipitated by (B) vimentin or (C) Snail as described in Materials and Methods. Associated ubiquitin was detected by Western blot assay. Data represent at least three independent experiments.