Abstract：
OBJECTIVE: To understand the mechanism of prostaglandin E2 (PGE2)-mediated immunosuppression in dendritic cells (DCs).
METHODS: In vivo experiments were conducted on 4T1 tumor bearing mice (TBM). In vitro experiments were performed in bone marrow-derived DCs (BMDCs), or spleen cells. Cytokines were monitored by ELISA/ELIspot. Gene expression was monitored by RT-PCR/flow cytometry.
RESULTS: In silico, in vitro, and in vivo experiments in 4T1 TBM revealed that PGE2 induced IL-6/pSTAT3 signaling through EP4 receptors in DCs, resulting in their dysfunction. These effects were reversed by EP4 antibody neutralization, EP4 antagonist, and STAT3 inhibitory peptides. PGE2 induced IL-6 was regulated by miR-365, as its mimic inhibited PGE2 induced IL-6 and the inhibitor increased lL-6 levels in DC. Bio-informatic analysis in human mammary cancers also revealed a strong compared co-relation between PGE2 and IL-6 (Correlation AnalyzeR) (R = 0.94). Mice bearing PTGS-2 KD 4T1 tumors had decreased tumor burden, PGE2, EP4, IL-6, and pSTAT3 signaling, along with improved DCs and T cell functions. Treatment of mice with a cyclooxygenase-2 (COX-2) inhibitor or EP4 antagonist decreased tumor burden, and this effect of EP4 antagonist was abrogated upon in vivo depletion of CD11c cells, indicating the crucial role of PGE2 signaling in DCs in tumor progression.
CONCLUSIONS: In summary, our data highlights the importance of dendritic cells in mediating PGE2-mediated immunosuppression and the use of EP4 or STAT3 inhibitors or miR365 mimics can restore immunogenicity in cancer.
METHODS: In vivo experiments were conducted on 4T1 tumor bearing mice (TBM). In vitro experiments were performed in bone marrow-derived DCs (BMDCs), or spleen cells. Cytokines were monitored by ELISA/ELIspot. Gene expression was monitored by RT-PCR/flow cytometry.
RESULTS: In silico, in vitro, and in vivo experiments in 4T1 TBM revealed that PGE2 induced IL-6/pSTAT3 signaling through EP4 receptors in DCs, resulting in their dysfunction. These effects were reversed by EP4 antibody neutralization, EP4 antagonist, and STAT3 inhibitory peptides. PGE2 induced IL-6 was regulated by miR-365, as its mimic inhibited PGE2 induced IL-6 and the inhibitor increased lL-6 levels in DC. Bio-informatic analysis in human mammary cancers also revealed a strong compared co-relation between PGE2 and IL-6 (Correlation AnalyzeR) (R = 0.94). Mice bearing PTGS-2 KD 4T1 tumors had decreased tumor burden, PGE2, EP4, IL-6, and pSTAT3 signaling, along with improved DCs and T cell functions. Treatment of mice with a cyclooxygenase-2 (COX-2) inhibitor or EP4 antagonist decreased tumor burden, and this effect of EP4 antagonist was abrogated upon in vivo depletion of CD11c cells, indicating the crucial role of PGE2 signaling in DCs in tumor progression.
CONCLUSIONS: In summary, our data highlights the importance of dendritic cells in mediating PGE2-mediated immunosuppression and the use of EP4 or STAT3 inhibitors or miR365 mimics can restore immunogenicity in cancer.
摘要：
目的：了解前列腺素E2（PGE2）介导的树突状细胞（DC）免疫抑制机制。
方法:对4T1荷瘤小鼠(TBM)进行体内实验。在骨髓来源的DC（BMDCs）中进行了体外实验，或脾细胞。通过ELISA/ELIspot监测细胞因子。通过RT-PCR/流式细胞术监测基因表达。
结果：在计算机上，在体外，4T1TBM体内实验显示PGE2通过EP4受体在DCs中诱导IL-6/pSTAT3信号传导,导致他们的功能障碍。这些效应被EP4抗体中和逆转，EP4拮抗剂，和STAT3抑制肽。PGE2诱导的IL-6可以被miR-365调节，因为其模拟物抑制PGE2诱导的IL-6，并且抑制剂增加DC中IL-6的水平。人类乳腺癌的生物信息学分析也揭示了PGE2和IL-6之间的强比较相关性(相关分析R)(R=0.94)。携带PTGS-2KD4T1肿瘤的小鼠肿瘤负荷降低，PGE2，EP4，IL-6和pSTAT3信号，以及改善的DC和T细胞功能。用环氧合酶-2（COX-2）抑制剂或EP4拮抗剂治疗小鼠可降低肿瘤负荷，EP4拮抗剂的这种作用在体内清除CD11c细胞后被消除，表明PGE2信号在DCs中在肿瘤进展中的关键作用。
结论：总之，我们的数据强调了树突状细胞在介导PGE2介导的免疫抑制和EP4或STAT3抑制剂中的重要性,或者使用miR365模拟物可以恢复癌症中的免疫原性.
方法:对4T1荷瘤小鼠(TBM)进行体内实验。在骨髓来源的DC（BMDCs）中进行了体外实验，或脾细胞。通过ELISA/ELIspot监测细胞因子。通过RT-PCR/流式细胞术监测基因表达。
结果：在计算机上，在体外，4T1TBM体内实验显示PGE2通过EP4受体在DCs中诱导IL-6/pSTAT3信号传导,导致他们的功能障碍。这些效应被EP4抗体中和逆转，EP4拮抗剂，和STAT3抑制肽。PGE2诱导的IL-6可以被miR-365调节，因为其模拟物抑制PGE2诱导的IL-6，并且抑制剂增加DC中IL-6的水平。人类乳腺癌的生物信息学分析也揭示了PGE2和IL-6之间的强比较相关性(相关分析R)(R=0.94)。携带PTGS-2KD4T1肿瘤的小鼠肿瘤负荷降低，PGE2，EP4，IL-6和pSTAT3信号，以及改善的DC和T细胞功能。用环氧合酶-2（COX-2）抑制剂或EP4拮抗剂治疗小鼠可降低肿瘤负荷，EP4拮抗剂的这种作用在体内清除CD11c细胞后被消除，表明PGE2信号在DCs中在肿瘤进展中的关键作用。
结论：总之，我们的数据强调了树突状细胞在介导PGE2介导的免疫抑制和EP4或STAT3抑制剂中的重要性,或者使用miR365模拟物可以恢复癌症中的免疫原性.
