ABSTRACT
Purpose To study the reversal effect on multidrug resistance (MDR) by TNF-α gene combined with verapamil (VRP) or tamoxifen (TAM). Methods By using recombinant retrovirus vector, TNF-α gene was transfected into multidrug-resistant human breast cancer cell line MCF7/ADR. The TNF-α secreting cell clone MCF7/ADR-TNF was obtained by G418 screening. The integrating and secreting of TNF-α were analyzed by PCR and ELISA. MTT assay and formula"I = d/D1 + d/D2" were used to evaluate the reversal effect of multidmg resistance with TNF-α gene combined with verapamil or tamoxifen. ResultsThe level of TNF-α secreted by MCF7/ADR-TNF was 1 737 pg/ml (106cells/48 h). Compared with control,the resistance to ADR of MCF7/ADR-TNF was reversed by 1.6 times. The reversal effect produced by combination of TNF-α gene and VRP was antagonistic. The combination of TNF-α gene and TAM produced synergic effect (interaction index I = 0.64). ConclusionsTNF-α gene combined with TAM has synergic effect on reversing MDR.
ABSTRACT
We compared the ability of tumorigenicity of TNF-? gene-modified and unmodified H22 tumor cells, and therapeutic functions of the irradiated cells. Results indicated that H22-TNF-? cells were less tumorigenic as compared to H22 and H22-LXSN cells. In case of treatment groups, injected with irradiated tumor vaccine in 3 or 6 days after inoculation of H22 cells, the tumor growth was suppressed.
ABSTRACT
Retroviral vector was used to introduce the interleukin - 2 (IL -2) gene into H22 cells, a BALB/c mouse hepatoma cell line. The IL-2 gene and marker gene (NeoR) were assessed by using PCR and RT-PCR methods. FACS analysis demonstrated that the cells with low DNA content in IL-2 gene modified H22 cells were more than these in control H22 cells. Electron microscopic morphological structure showed that some cells in IL-2 gene modified H22 went into apoptotic cell death. The study demonstrated that apoptotic cell death of H22 - IL-2 cells was induced by the IL-2 gene modification. It may be one of mechanisms of decreased tumorigenicity of IL - 2 gene modified tumor cells.