Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, ul. R. Weigla 12, 53-114, Wroclaw, Poland.
J Exp Clin Cancer Res. 2018 Jun 28;37(1):126. doi: 10.1186/s13046-018-0799-y.
The excessive amounts of immunosuppressive factors present in a tumor microenvironment (TME) reduce the effectiveness of cancer vaccines. The main objective of our research was to improve the effectiveness of dendritic cell (DC)-based immunotherapy or chemoimmunotherapy composed of cyclophosphamide (CY) and DCs by application of lentivectors encoding shRNA specific to IL-10 (shIL10 LVs) in murine colon carcinoma MC38 model.
The efficacy of shIL10 LVs in silencing of IL-10 expression was measured both in vitro and in vivo using Real-Time PCR and ELISA assays. In addition, the influence of intratumorally inoculated lentivectors on MC38 tumor microenvironment was examined using flow cytometry method. The effect of applied therapeutic schemes was determined by measurement of tumor growth inhibition and activation state of local and systemic immune response.
We observed that intratumorally inoculated shIL10 LVs transduced tumor and TME-infiltrating cells and reduced the secretion of IL-10. Application of shIL10 LVs for three consecutive weeks initiated tumor growth inhibition, whereas treatment with shIL10 LVs and BMDC/TAg did not enhance the antitumor effect. However, when pretreatment with CY was introduced to the proposed scheme, we noticed high MC38 tumor growth inhibition accompanied by reduction of MDSCs and Tregs in TME, as well as activation of potent local and systemic Th1-type antitumor response.
The obtained data shows that remodeling of TME by shIL10 LVs and CY enhances DC activity and supports them during regeneration and actuation of a potent antitumor response. Therefore, therapeutic strategies aimed at local IL-10 elimination using lentiviral vectors should be further investigated in context of combined chemoimmunotherapies.
肿瘤微环境（TME）中存在大量免疫抑制因子，降低了癌症疫苗的疗效。我们研究的主要目的是通过应用编码针对白细胞介素 10（IL-10）的短发夹 RNA（shRNA）的慢病毒载体（shIL10 LVs）来提高基于树突状细胞（DC）的免疫疗法或包含环磷酰胺（CY）和 DC 的化疗免疫疗法的疗效，在鼠结肠癌细胞 MC38 模型中。
使用实时 PCR 和 ELISA 检测体外和体内 shIL10 LVs 沉默 IL-10 表达的效果。此外，使用流式细胞术检测肿瘤内接种的慢病毒对 MC38 肿瘤微环境的影响。通过测量肿瘤生长抑制和局部和全身免疫反应的激活状态来确定应用治疗方案的效果。
我们观察到肿瘤内接种的 shIL10 LVs 转导肿瘤和 TME 浸润细胞，并减少 IL-10 的分泌。连续三周应用 shIL10 LVs 可启动肿瘤生长抑制，而用 shIL10 LVs 和 BMDC/TAg 治疗并未增强抗肿瘤作用。然而，当将 CY 预处理引入该方案时，我们注意到 MC38 肿瘤的高生长抑制，同时 TME 中的 MDSCs 和 Tregs 减少，以及强大的局部和全身 Th1 型抗肿瘤反应的激活。
获得的数据表明，shIL10 LVs 和 CY 通过重塑 TME 增强了 DC 的活性，并在它们的再生和启动强大的抗肿瘤反应期间支持它们。因此，使用慢病毒载体针对局部 IL-10 消除的治疗策略应在联合化疗免疫疗法的背景下进一步研究。
