Observation on the Biological Characteristics of the Tumor Cells Transfected with Tumor Necrosis Factor-? Gene by Retrovirus / 中国肿瘤生物治疗杂志

ABSTRACT

The in vivo tumorigenicity of murine B16 melanoma cells engineered to secret TNF-a was observed. The retrovirus containing mouse TNF-a cDNA was generated by the virus-packing cell PA317 transfected with plasmid pXT-TNF. The B16 cell clone secreting the highest TNF-a level was obtained after G418 resistance selection, limiting dilution and the assay of TNF-a activity. After the mice were inoculated subcutaneously with the cell clone, we found the tumor growth was inhibited and the survival period of the mice extended when compared with the mice inoculated with the wild-type B16 cells . We also found that the tuinorigenicity of B16-TNF-a+ cell was associated with the cell number inoculated. At or above the 1.25? 104 cells, the percentage of the mice with detectable tumor correlated negatively with the cell number inoculated however, at the 6.25 ? 103 cells, the percentage was higher than that at 2.5?10~(4) cells. These results encourage us to do further experiments on the following tumor cell-targeted TNF-a gene therapy.