Figure 5: Effect of cucurbitacin B on p21 protein expression in breast cancer cells. (a) Cells were treated with cucurbitacin B for 48 hr, and then the total proteins were extracted and performed western blotting to analyze expression. Tubulin was used as an equal loading control. (b) Densitometric analyses of expression of relative to the untreated control. versus nontreated control, versus nontreated control.