基于TLR4信号通路黄芪多糖促树突状细胞抗肿瘤作用的研究

Anti-tumor effect study of Astragalus polysaccharide promotes dendritic cell through TLR4 signal pathway

关键词:  黄芪多糖  树突状细胞  TLR4通路  抗肿瘤

Key words:  Astragalus polysaccharides  dendritic cell  TLR4 pathway  anti-tumor

摘要:

[目的] 研究基于Toll样受体4（TLR4）信号通路黄芪多糖（APS）活化树突状细胞（DCs）发挥抗肿瘤作用的机制。[方法] 将树突状细胞DC2.4随机分为空白（Control）组、APS组、肿瘤坏死因子-α（TNF-α）组、APS+TNF-α组、TAK-242＋TNF-α组、TAK-242＋APS＋TNF-α组、ST2825＋TNF-α组及ST2825＋APS＋TNF-α组，干预72 h后，流式细胞仪检测DCs表型CD80、CD86的表达情况，ELISA法检测DCs对细胞因子白细胞介素（IL）-12分泌水平的影响。将上述干预处理后的DCs和T细胞共培养，ELISA法检测DCs对T细胞活化影响；将活化的细胞毒性T淋巴细胞（CTL）与肿瘤细胞CT 26共培养，全视野细胞成像分析仪检测CTL对肿瘤的杀伤作用。[结果] 与Control组相比，APS可显著促进DCs表面分子CD80和CD86的表达以及IL-12的分泌（P<0.05），且APS和TNF-α协同干预时，效果最优。此外，两者协同干预的DCs可显著促进T细胞增殖并分泌IL-2，增强CTL对肿瘤的杀伤（P<0.05）。然而，加入TLR4通路阻断剂TAK-242或ST2825后，APS+TNF-α组DCs表面分子CD80和CD86的表达、IL-12的分泌水平与TNF-α组相比均无显著差异，且两者协同干预的DCs对T细胞增殖、分泌IL-2及肿瘤的杀伤水平亦无显著差异。[结论] APS可能是通过TLR4介导的髓样分化因子（MyD88）通路促进DCs成熟、活化，激活T细胞，进而发挥抗肿瘤的作用。

Abstract:

[Objective] The aim of this study is to investigate the anti-tumor effect of Astragalus polysaccharides (APS) activated dendritic cell (DCs) via the TLR4 signaling pathway. [Methods] The DC2.4 were randomly divided into Control group,APS group,TNF-α group,APS+TNF-α group,TAK-242+TNF-α group,TAK-242+APS+TNF-α group,ST2825+TNF-α group and ST2825+APS+TNF-α group. After 72h of intervention,the ratio of CD80+CD86+ DCs were detected by flow cytometry,and the effect of DCs on the secretion of cytokine IL-12 were detected by ELISA. Then the DCs in previous step were co-cultured with T cells,and effects of DCs on T cell activation were detected by ELISA;the activated CTL cells were co-cultured with tumor cells CT 26,tumor-cell-killing efficiency was calculated using the full-field cell imaging analyzer. [Results] Compared with the control group,APS can significantly promote the expression of CD80+CD86+ DCs and the secretion of IL-12 (P<0.05),and the best effects were obtained when APS and TNF-α were synergistically intervened. In addition,the DCs intervened by APS+TNF-α could significantly promote proliferation of T cells,the secretion of IL-2 by T cells and enhance the killing of tumors by CTL (P<0.05). However,after adding the TLR4 pathway blocker TAK-242 or ST2825,the expression of CD80+CD86+ DCs and the secretion level of IL-12 in APS+TNF-α group were not significantly different from those in the TNF-α group. Compared with the TNF-α group,there was no significant difference in proliferation of T cells,the level of IL-2 secretion and tumor killing by T cells in APS+TNF-α group with blocker TAK-242 or ST2825. [Conclusion] APS could induce DCs maturation and increase the activating ability of DC on T cells. These effects and mechanism may through TLR4/MyD88 pathway,and APS/TNF-a combination treatment to DCs is the best.