Creation of rabbit bone and soft tissue tumor using cultured VX2 cells

Background: To create rabbit VX2 bone tumors, it is surgically less demanding to implant VX2 cell suspensions than minced tumor fragments. A VX2 cell line that can be expanded using standard cell culture techniques might provide an unlimited supply of cells needed to create these bone tumors. Therefore, the aim of the present study was to establish a VX2 cell line and verify its tumorigenicity in an athymic mouse and rabbit animal model.

Materials and methods: Minced VX2 tumor fragments were allowed to grow as a monolayer in 10 mL Dulbecco's modified Eagle medium/nutrient mixture F-12 (1:1) supplemented with 10% fetal calf serum and passaged multiple times. The tumorigenecity of the cultured VX2 cells were tested in athymic mice (intradermal tumor development) and in New Zealand white rabbits (bone and soft tissue tumor model).

Results: The VX2 cells proliferated rapidly in tissue culture flasks containing Dulbecco's modified Eagle medium/nutrient mixture F-12 medium supplemented with 10% fetal bovine serum. After reaching confluence, the VX2 cells can only be subcultured when plated at a greater density (e.g., at a dilution of 1:1). All 6 athymic mice developed tumors within 15 d of VX2 cell suspension implantation. In the rabbits, the VX2 cells were able to produce tumors in muscle tissue and in the distal femurs but not in the proximal tibia.

Conclusions: VX2 cell lines can be successfully created from VX2 tumor fragments and passaged multiple times. In contrast to previous reports, the VX2 cells grown in vitro are capable of maintaining their tumorigenecity. However, successful tumor growth might depend on the initial number of cells implanted and the use of extracellular matrices for tumor proliferation.