干扰素调节因子 1 对肿瘤来源的外泌体的激活增强了抗肿瘤免疫反应。

Interferon regulatory factor 1 priming of tumour-derived exosomes enhances the antitumour immune response.

机构信息

Thomas E. Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA 15260, USA.

Department of General Surgery, Tenth People's Hospital affiliated to Tongji University, Shanghai 200072, China.

出版信息

Br J Cancer. 2018 Jan;118(1):62-71. doi: 10.1038/bjc.2017.389. Epub 2017 Nov 7.

BACKGROUND

Tumour-derived exosomes (TEXs) have a potential for application in cancer vaccines. Whether TEXs after induction by interferon regulatory factor 1 (IRF-1) are capable of enhancing the antitumour response remains to be determined.

METHODS

Exosomes released by tumour cells infected with IRF-1-expressing adenovirus (IRF-1-Exo) or treated with interferon-γ (IFN-Exo) were isolated via ultracentrifugation. The IRF-1 target proteins IL-15Rα and MHC class I (MHC-I) were analysed by western blot. Exosomes along with CpG adjuvant were injected into tumour models to assess the antitumour effects. Tumours were harvested for immunofluorescence staining. Splenocytes from tumour-bearing mice were co-cultured with tumour cells. The IFNγ-positive and granzyme B-positive CD8α+ splenocyte cells were quantified by flow cytometry.

RESULTS

The IRF-1-Exo or IFN-Exo displayed increased IL-15Rα and MHC-I expression. Injection of IRF-1-Exo or IFN-Exo combined with CpG had improved antitumour effects in mice. This effect may be a result of increased infiltration of tumours by CD4+ and CD8α+ T cells. Antibody-mediated depletion of CD4+ or CD8+ T cells abrogated the antitumour effects. Splenocytes isolated from CpG+IRF-1-Exo-injected Hepa 1-6 tumour mice had increased IFNγ-positive and granzyme B-positive CD8+ cells after co-culturing with Hepa 1-6 cells as compared with MC38 cells.

CONCLUSIONS

The IRF-1 priming of TEXs enhances antitumour immune response.

背景

肿瘤衍生的外泌体（TEXs）在癌症疫苗中有应用潜力。由干扰素调节因子 1（IRF-1）诱导的 TEX 是否能够增强抗肿瘤反应仍有待确定。

方法

通过超速离心分离感染表达 IRF-1 的腺病毒（IRF-1-Exo）或用干扰素-γ（IFN-Exo）处理的肿瘤细胞释放的外泌体。通过 Western blot 分析 IRF-1 靶蛋白白细胞介素 15 受体 α（IL-15Rα）和 MHC Ⅰ类（MHC-I）。将外泌体与 CpG 佐剂一起注射到肿瘤模型中以评估抗肿瘤作用。采集肿瘤进行免疫荧光染色。用肿瘤细胞共培养荷瘤小鼠的脾细胞。通过流式细胞术定量 IFNγ 阳性和颗粒酶 B 阳性 CD8α+脾细胞。

结果

IRF-1-Exo 或 IFN-Exo 显示出增加的 IL-15Rα 和 MHC-I 表达。IRF-1-Exo 或 IFN-Exo 联合 CpG 的注射在小鼠中增强了抗肿瘤作用。这种作用可能是由于 CD4+和 CD8α+T 细胞更多地浸润肿瘤所致。CD4+或 CD8+T 细胞的抗体耗竭消除了抗肿瘤作用。与 MC38 细胞相比，从 CpG+IRF-1-Exo 注射 Hepa 1-6 肿瘤小鼠分离的脾细胞在与 Hepa 1-6 细胞共培养后具有更多的 IFNγ 阳性和颗粒酶 B 阳性 CD8+细胞。