In vivo xenograft tumor assays

For xenograft studies, 6- to 8-week-old female athymic nude mice were used. All animal experiments were performed under protocols approved by the National Cancer Institute Animal Care and Use Committee. Five million of the THJ-11T or THJ-16 cells in 200 μl 50% Matrigel basement membrane matrix (BD Biosciences, Cat. 354234) were inoculated subcutaneously into the right flank of mice 2 to 3 weeks before treatment. The treatment with vehicle, PLX, PD, or both PLX and PD started when the median tumor size reached approximately 100-150 mm³. PLX was administered via oral gavage at a dose of 24 mg/kg/mouse per day. PD was administered via oral gavage at a dose of 1 mg/kg/mouse per day. The tumor size was measured with a caliper every 1-4 days. The mice were treated either for a short-term duration or long-term duration. For the short-treatment, mice inoculated with THJ-11T or THJ-16T cells were treated with PLX, PD or the combination of the two drugs for 24 days or 14 days, respectively. For long-term treatment, mice inoculated with THJ-11T cells were received treatment uninterrupted for 48 days in one group, or in another group, mice were treated for 20 days followed by termination of the treatment, but were continued to be monitored for the tumor progression. All mice were euthanized at the end of the treatment outlined above and the tumors were dissected for further analysis.