In vivo metastasis experiments

Female virgin FVB/NJ or BALB/cJ mice were obtained from Jackson Laboratory, and athymic NCI Nu/Nu from NCI Frederick at 6–8 weeks of age. Two days prior to in vivo experiments, cells were plated at 1 x 10⁶ cells/condition into T-75 flasks (Corning) in non-selective DMEM. A total of 100,000 cells per mouse was injected into the fourth mammary fat pad of FVB/NJ (MET1 and 6DT1 cells), BALB/cJ (4T1 cells) mice. The mice were euthanized between 28–30 days post-injection. Primary tumors were resected, weighed, and lung metastases counted. Statistical significance was calculated with a Kruskal-Wallis test followed by Conover Inman test. All animal experiments were performed in compliance with the National Cancer Institute's Animal Care and Use Committee guidelines.