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 𝑝 2 1 expression. Tubulin was used as an equal loading control. (b) Densitometric analyses of expression of 𝑝 2 1 relative to the untreated control. 𝑃 < 0 . 0 5 versus nontreated control, 𝑃 < 0 . 0 1 versus nontreated control.