Figure 3

Apigenin antitumor activity associated with inhibition of proteasomal activity and induction of apoptosis in vivo. Female nude mice bearing MDA-MB-231 cell tumors were treated with the solvent control (Sol) or with 25 or 50 mg/kg/day apigenin (Api 25, Api 50) for 29 days. Tumors were collected after 29 days of treatment, and the prepared tissues were analyzed by multiple assays. (a) Inhibition of MDA-MB-231 tumor growth by apigenin. (b) Proteasomal chymotrypsin (CT)-like activity measured in the tumor samples. (c) Western blot analysis for accumulation of ubiquitinated proteins (Ub-Prs), Bax, IκBα and actin presented three representative individual tumor samples from each group of mice. (d) Immunohistochemistry for p27 and terminal nucleotidyl transferase-mediated nick end labeling (TUNEL). Data points, mean tumor volume in each experimental group containing four mice; bars, standard deviation. *P < 0.05, **P < 0.01. Number under each band of the western blot indicates a quantitative analysis by densitometry compared with the loading control of actin.