RESUMO
ObjectiveTo explore the mechanism of Si Junzitang in regulating the expression of NKG2A to affect the anti-colon cancer function of natural killer （NK） cells. MethodNK cells isolated from healthy honors were cultured and used to construct the three incubation models of NK cells， human colon cancer HCT116 cells， and NK cells + HCT116 cells （co-incubation）. real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） was conducted to determine the mRNA levels of natural killer group 2 member A （NKG2A） and interleukin （IL）-15 in NK cells， as well as the mRNA level of histocompatibility leucocyte antigen E （HLA-E） in HCT116 cells. The secretion of IL-15 was detected by enzyme-linked immunosorbent assay （ELISA）. Methyl thiazolyl tetrazolium （MTT） assay was employed to determine the applicable concentration of IL-15 and test the effects of Si Junzitang and IL-15 on the activities of NK cells and the HCT116 cells in the co-incubation model. The effects of Si Junzitang and IL-15 on the mRNA levels of NKG2A in NK cells and HLA-E in HCT116 cells were detected by Real-time PCR. Monalizumab （M， anti-NKG2A mab） was used to block the NKG2A-HLA-E pathway in co-incubation model， and then the proliferation of HCT116 cells was detected by MTT assay. ResultThe interaction of NK cells and HCT116 cells up-regulated the mRNA levels of NKG2A in NK cells and HLA-E in HCT116 cells （P<0.05）， as well as the expression level and secretion of IL-15 （P<0.05）. Compared with the blank group， Si Junzitang and Si Junzitang + IL-15 promoted the proliferation and improved the anti-colon cancer function of NK cells （P<0.01）. Furthermore， they down-regulated the mRNA levels of NKG2A in NK cells and HLA-E in the HCT116 cells co-incubated with NK cells （P<0.01）. M and IL-15 + M inhibited the proliferation of HCT116 cells compared with the groups without M （P<0.01）. ConclusionThe interaction of NK cells and HCT116 cells can induce activation of NKG2A-HLA-E pathway to impair NK cell function. Si Junzitang can inhibit the activation of NKG2A-HLA-E pathway to restore the anti-colon cancer function of NK cells.
RESUMO
BACKGROUND: Natural killer (NK) cells are an emerging new tool for cancer immunotherapy. To develop NK cell therapeutics from peripheral blood mononuclear cells (PBMCs) of healthy donors, substantial expansion of primary NK cells is necessary because of the very low number of these cells in peripheral blood. In this study, we aimed to investigate the effect of various cytokine alone or combinations, in expanded NK cells and to analyze the synergetic effect of cytokine combinations. METHODS: Human NK cells were isolated from healthy donor PBMC. Purified NK cells were stimulated with single cytokines or combinations of IL-2, IL-15, IL-18, and IL-27. The expanded NK cells were characterized by flow cytometry, cytotoxicity assay, calcein AM assay and Western blot. RESULTS: We investigated the synergistic effects of each cytokine, namely, IL-2, IL-15, IL-18, and IL-27, on human NK cells isolated from PBMCs of healthy donors and cultured for 21 days. We identified that IL-15/IL-18/IL-27-mediated activation of NK cells most potently increased NK cell proliferation, cytotoxicity, and IFN-É£ secretion compared with the activation observed with other treatments, including IL-2, IL-15, and IL-15/IL-18. Additionally, the expression of DNAM-1, NKG2D, CD69, and natural cytotoxicity receptors (NCRs; NKp30 and NKp44) increased on day 21 compared to that on day 0, demonstrating the activation of NK cells. In vitro, expanded NK cells were highly cytotoxic against cancer cells, displaying increased perforin and granzyme B accumulation. CONCLUSIONS: Taken together, these results indicated that IL-27 can synergize on NK cell expansion and activation with IL-15 and IL-18. In addition, we described an improved culture method for ex vivo expansion of human NK cells with IL-15/IL-18/IL-27 stimulation and characterized the response of NK cells to this stimulation.