Nanosecond pulsed electric field inhibits malignant melanoma growth by inducing the change of systemic immunity

BACKGROUND: Nanosecond pulsed electric fields (nsPEFs) showed an inhibitory effect on proliferation of malignant melanoma. In this study, the growth of melanoma were inhibited by changing the systemic immunity. MATERIAL AND METHODS: C57BL/6 mice with B16 malignant were exposed to 200 pulses of 100 ns duration, 30kV/cm. The mice were executed four days later. T lymphocyte has been extracted from spleen. Cell viability was evaluated by CCK-8 assay. CD3+CD4+ T cells, CD3+CD8+ T cells, regulatory T cells (Treg) and myeloid-derived suppressor cells (MDSC) were analyzed by flow cytometry. TNF-α, IL-2, IL-10, TGF-β, IFN– γ levels in supernatants were assessed by ELISA. RESULTS: C57 malignant melanoma model were established successfully. After the treatment of nsPEFs(30 kV/cm 100 ns 200p), the numbers of T lymphocytes were increased.CD3+ CD4+ T cells changed from 48% to 51.2%;CD3+CD8+T lymphocytes increased from 39.6% to 40.4%.Treg cells reduced from 4.3% to 2.4%,MDSC decreased by 39.0% to 19.7% . In addition, the level of TNF-α, IL-2 were increased (P< 0.05) and the level of IL-10 were decreased (P<0.05) and the level of TGF-β and IFN-γ remained stable (P>0.05). CONCLUSIONS: Tumor growth can be effectively inhibited by nsPEFs in vivo, which activate targets of immune respones, accumulation of inflammatory cells and immune cytokines. Key words:Nanosecond pulsed electric fields, melanoma, immune cytokines.