Fig. 6.

Effect of apigenin administration on PC-3 tumor growth and apoptosis in athymic nude mice. a Tumor volume after apigenin administration. Approximately 1 million cells were injected into both flanks of each mouse to initiate ectopic tumors, and apigenin was provided to the animals 2 weeks after tumor implantation mimicking therapeutic regimen. Mice were fed ad libitum with Teklad 8760 autoclaved high-protein diet. Apigenin was provided with 0.5 % methyl cellulose and 0.025 % Tween 20 as vehicle to these animals per-oral on a daily basis. Group I, control, received 0.2 ml vehicle only, Group II received 20 μg/day apigenin per mouse in 0.2 ml vehicle and Group III received 50 μg/day apigenin per mouse in 0.2 ml vehicle daily for 8 weeks. Tumor size was measured weekly in two dimensions throughout the study. b Wet weight of tumors is represented as the mean of 6–8 tumors from each group, quantitative measurement of apoptosis as demonstrated by M30 reactivity. The experiment was repeated twice in duplicate with similar results. Bars represent mean ± SD **P < 0.001 versus control. c Western blotting for XIAP, surviving, HDAC1, Bax and PARP cleavage in tumor lysates after apigenin administration at the indicated doses. β-actin was used as loading control. Numeric values represent protein levels normalized to the loading control (β-actin). The details are provided in “Materials and methods” section