ABSTRACT

Background: Dendritic cells (DCs) play an essential role in the induction and regulation of immune responses, including the activation of effector T lymphocytes for the eradication of cancers. However, the tumor microenvironment (TME) often leads to DCs dysfunction due to their immature state. MicroRNA-155 (miR-155) has emerged as a typical multifunctional gene regulator associated with immune system development and immune cell activation and differentiation.

Methods: In this study, a three-dimensional TME model that closely mimics the microenvironment of breast cancer was prepared. MiR-155 overexpression and control vectors were constructed using lentivirus. The relative expression of miR-155 was determined by qRT-PCR. Cell viability, antigen uptake and cell surface marker expression were analyzed by live-dead staining and flow cytometry. The migration ability of bone marrow-derived DCs (BMDCs) was qualified by transwell assay. A mixed lymphocyte culture assay was used to assess T cell-specific proliferation. Cytokine levels were determined by ELISA.

Results: We found that the expression of miR-155 in DCs was inhibited by the TME. Furthermore, upregulation of miR-155 enhanced the migration ability, uptake of antigen and elevated the expression of the mature DCs markers CD80 and MHCII. More importantly, overexpression of miR-155 in DCs significantly induced T cell proliferation and IFN-γ and IL-2 secretion.

Conclusion: MiR-155 is a potential molecular regulator that may improve the efficacy of DCs-based tumor immunotherapy.

摘要

背景：树突状细胞 (DC) 在免疫反应的诱导和调节中发挥重要作用，包括激活效应 T 淋巴细胞以消除癌症。然而，肿瘤微环境（TME）由于其不成熟状态而经常导致DCs功能障碍。MicroRNA-155 (miR-155) 已成为与免疫系统发育和免疫细胞活化和分化相关的典型多功能基因调节剂。

方法：在本研究中，制备了一个与乳腺癌微环境非常相似的三维 TME 模型。使用慢病毒构建 MiR-155 过表达和对照载体。通过qRT-PCR确定miR-155的相对表达。通过活-死染色和流式细胞术分析细胞活力、抗原摄取和细胞表面标志物表达。骨髓源性 DCs (BMDCs) 的迁移能力通过 transwell 测定法进行了鉴定。混合淋巴细胞培养试验用于评估 T 细胞特异性增殖。通过ELISA确定细胞因子水平。

结果：我们发现 TME 抑制了 DCs 中 miR-155 的表达。此外，miR-155的上调增强了迁移能力、抗原的摄取，并提高了成熟DCs标志物CD80和MHCII的表达。更重要的是，miR-155 在 DCs 中的过表达显着诱导了 T 细胞增殖和 IFN-γ 和 IL-2 的分泌。

结论： MiR-155 是一种潜在的分子调节剂，可提高基于 DCs 的肿瘤免疫治疗的疗效。