Meng Yiming, Gao Xinghua, Chen Wenna, Plotnikoff Nicolas P, Griffin Noreen, Zhang Guirong, Shan Fengping
Department of Immunology, School of Basic Medical Science, China Medical University, No. 77, Puhe Road, Shenyang 110122, China; Center of Biological Therapy, Cancer Hospital of China Medical University, No. 44, Xiaoheyan Road, Shenyang 110042, Liaoning Province, China.
Department of Dermatology, No. 1 Hospital, China Medical University, No. 92, North Second Road, Shenyang 110001, China.
Int Immunopharmacol. 2017 Mar;44:61-71. doi: 10.1016/j.intimp.2017.01.004. Epub 2017 Jan 12.
MENK, an endogenous opioid peptide has been reported to have many immunological and antitumor activities. So far the detailed mechanisms of antitumor through regulating DCs by MENK have not been elucidated yet. The aim of this work was to investigate the antitumor mechanisms of MENK via regulating DC. The monitoring methods, such as ELISA, MTS assay, CFSE, Real-time PCR and Western blot were included in our research. We found bone marrow derived dendritic cells (BMDCs) in 36 female C57BL/6 mice treated with MENK enhanced expression of key surface molecules, increased production of critical cytokines reduced endocytosis of FITC-dextran, upregulated TLR4 through MyD88/NF-κB signaling pathway and mounted higher antitumor activity. These observations were further supported by an enhancement of nuclear translocation of the p65NF-κB subunit involved in this process. Surprisingly, mu-opioid receptors were the main participants of this kind of activation, not delta-opioid receptors nor kappa-opioid receptors, and these interactions could be partly blocked by Naltrexone (a kind of opioid antagonist). In vivo study the activated CD4, CD8T cells and decreased ability to induce differentiation of Foxp3 regulatory T cells were detected post treatment of MENK. Thus, it is concluded that MENK could exert antitumor effect through precisely regulating opioid receptor mediated functions of DCs. In addition, MENK treated DCs may serve as a new immunotherapy approach against tumor.
据报道，内源性阿片肽MENK具有多种免疫和抗肿瘤活性。迄今为止，MENK通过调节树突状细胞（DCs）发挥抗肿瘤作用的详细机制尚未阐明。本研究旨在探讨MENK通过调节DCs发挥抗肿瘤作用的机制。我们的研究采用了ELISA、MTS检测、CFSE、实时PCR和蛋白质免疫印迹等监测方法。我们发现，用MENK处理的36只雌性C57BL/6小鼠的骨髓来源树突状细胞（BMDCs）增强了关键表面分子的表达，增加了关键细胞因子的产生，降低了FITC-葡聚糖的内吞作用，通过MyD88/NF-κB信号通路上调了TLR4，并具有更高的抗肿瘤活性。参与这一过程的p65NF-κB亚基核转位增强进一步支持了这些观察结果。令人惊讶的是，μ-阿片受体是这种激活的主要参与者，而非δ-阿片受体和κ-阿片受体，并且这些相互作用可被纳曲酮（一种阿片拮抗剂）部分阻断。在体内研究中，MENK处理后检测到活化的CD4、CD8 T细胞以及诱导Foxp3调节性T细胞分化的能力下降。因此，得出结论：MENK可通过精确调节阿片受体介导的DCs功能发挥抗肿瘤作用。此外，经MENK处理的DCs可能成为一种新的肿瘤免疫治疗方法。
