Characterization of MMTV-PyVT Tumor Cell Lines

Mammary tumors from MMTV-PyVT mice on the FVB/N background were minced and washed with DMEM containing fungizone (Invitrogen, Carlsbad, CA) and gentamycin (Invitrogen). The tumor pieces were plated in DMEM with 10% fetal calf serum plus antibiotics and incubated at 37°C in 5% CO₂ until tumor cells covered the dish. Single colonies were isolated, then expanded and characterized. Western blotting for E-cadherin and vimentin (antibodies from Sigma, St Louis, MO) confirmed epithelial origin of the clones. In order to assess their ability to grow in different organ microenvironments, cells from each line were injected into FVB/N mice in the mammary fat pad, tail vein or intra-tibially to assess orthotopic, pulmonary and bone growth, respectively. [n=3 for each organ site and cell line].