Aim: To explore the feasibility of RNA interference in the treatment of melanoma by inhibiting the Foxp3 gene expression in mouse B16 melanoma cells using RNA interference (RNAi) in vitro.
Methods: Small interfering RNA (siRNA) was designed according to Foxp3 gene. A short hairpin RNA (shRNA) lentivirus expression vector was constructed and transfected into mouse B16 cells, and RNA interference was induced in vitro. Western blot and real-time RT-PCR were performed to detect the expression of Foxp3 gene. ELISA was applied to detect the changes of TGF-β(1);, TGF-β(2);, IL-10 and other cytokines. The B16 cells after interference were co-cultured with CD4(+);CD25(-);T lymphocytes. CCK8 assay was used to monitor the proliferation of CD4(+);CD25(-);T lymphocytes.
Results: shRNA could suppress the expression level of Foxp3, down-regulate the inhibitory ability of tumor cells on the proliferation of CD4(+);CD25(-);T lymphocytes, and reduce the secretion of TGF-β(1);, TGF-β(2);, IL-10 and other cytokines, in particular the expression of TGF-β(2);.
Conclusion: RNA interference can inhibit the expression of target gene Foxp3 in mice melanoma cells and the proliferation of tumor cells. It can also reduce the inhibition on the proliferation of CD4(+);CD25(-);T lymphocytes, and the secretion of inhibitory cytokines.