To test the antitumor activity of PPARα antagonism in vivo, a subcutaneous xenograft mouse model is used. Caki-1 cells are implanted subcutaneously in nude (Nu/Nu) mice. After tumor masses reach ～5 mm in diameter, GW6471 is administrated intraperitoneally every other day for 4 wk at a dose (20 mg/kg mouse body wt) that is described to be effective in an in vivo dose-response study and confirmed here to be efficacious. There are significant differences in tumor growth between vehicle- and GW6471-treated animals. No toxicity is observed at the doses of GW6471 based on weights of the animals, and laboratory values, including kidney and liver function tests, are not adversely affected. To demonstrate on-target effects of GW6471, c-Myc levels are evaluated in the tumors, which show significant decreases in the GW6471-treated animals[3].
