Figure 1.

Experimental design for evaluating the chemopreventive effect of DFMO, licofelone, and the combination in NNK-induced lung cancer in the A/J mouse model. Six-week-old mice were injected intraperitoneally with NNK (10 μmol/mouse). Mice were maintained on AIN-76A diet for 3 weeks. Three weeks after NNK injection, mice were fed with control diet (AIN-76A) or experimental diets containing 1500 or 3000 ppm of DFMO, 200 or 400 ppm licofelone, or a low-dose combination of DFMO and licofelone. Treatment continued until the end of the study. At 17 weeks (10 mice/group) and at 34 weeks (15 mice/group) after NNK treatment excluding 3 weeks of wash out period after NNK treatment, mice were killed and lungs were harvested for evaluation of lung tumors. Detailed information is provided in the materials and methods section.