Preston A. Wells, Jr. Center for Brain Tumor Therapy, UF Brain Tumor Immunotherapy Program, University of Florida, Gainesville, FL, USA.
Neurosurgery Service, Hospital Cayetano Heredia, Lima, Peru.
J Immunother Cancer. 2019 Nov 21;7(1):321. doi: 10.1186/s40425-019-0809-4.
Dendritic cell (DC) vaccine efficacy is directly related to the efficiency of DC migration to the lymph node after delivery to the patient. We discovered that a naturally occurring metabolite, sarcosine, increases DC migration in human and murine cells resulting in significantly improved anti-tumor efficacy. We hypothesized that sarcosine induced cell migration was due to chemokine signaling.
DCs were harvested from the bone marrow of wild type C57BL/6 mice and electroporated with tumor messenger RNA (mRNA). Human DCs were isolated from peripheral blood mononuclear cells (PBMCs). DCs were treated with 20 mM of sarcosine. Antigen specific T cells were isolated from transgenic mice and injected intravenously into tumor bearing mice. DC vaccines were delivered via intradermal injection. In vivo migration was evaluated by flow cytometry and immunofluorescence microscopy. Gene expression in RNA was investigated in DCs via RT-PCR and Nanostring.
Sarcosine significantly increased human and murine DC migration in vitro. In vivo sarcosine-treated DCs had significantly increased migration to both the lymph nodes and spleens after intradermal delivery in mice. Sarcosine-treated DC vaccines resulted in significantly improved tumor control in a B16F10-OVA tumor flank model and improved survival in an intracranial GL261-gp100 glioma model. Gene expression demonstrated an upregulation of CXCR2, CXCL3 and CXCL1 in sarcosine- treated DCs. Further metabolic analysis demonstrated the up-regulation of cyclooxygenase-1 and Pik3cg. Sarcosine induced migration was abrogated by adding the CXCR2 neutralizing antibody in both human and murine DCs. CXCR2 neutralizing antibody also removed the survival benefit of sarcosine-treated DCs in the tumor models.
Sarcosine increases the migration of murine and human DCs via the CXC chemokine pathway. This platform can be utilized to improve existing DC vaccine strategies.
树突状细胞 (DC) 疫苗的疗效与 DC 递送至患者后向淋巴结迁移的效率直接相关。我们发现，一种天然存在的代谢产物肌氨酸可增加人源和鼠源细胞中的 DC 迁移，从而显著提高抗肿瘤疗效。我们假设肌氨酸诱导的细胞迁移是由于趋化因子信号。
从野生型 C57BL/6 小鼠的骨髓中采集 DC，并用电穿孔将肿瘤信使 RNA（mRNA）转染到 DC 中。从外周血单核细胞（PBMCs）中分离出人源 DC。用 20mM 肌氨酸处理 DC。从转基因小鼠中分离抗原特异性 T 细胞，并静脉注射到荷瘤小鼠中。通过皮内注射递送 DC 疫苗。通过流式细胞术和免疫荧光显微镜评估体内迁移。通过 RT-PCR 和 Nanostring 研究 DC 中的 RNA 基因表达。
肌氨酸显著增加了人源和鼠源 DC 的体外迁移。在体内，皮内递送后，肌氨酸处理的 DC 向淋巴结和脾脏的迁移明显增加。肌氨酸处理的 DC 疫苗可显著改善 B16F10-OVA 肿瘤侧翼模型中的肿瘤控制，并改善 GL261-gp100 胶质母细胞瘤模型中的存活。基因表达显示肌氨酸处理的 DC 中 CXCR2、CXCL3 和 CXCL1 表达上调。进一步的代谢分析表明环氧化酶-1 和 Pik3cg 上调。在人源和鼠源 DC 中加入 CXCR2 中和抗体可阻断肌氨酸诱导的迁移。CXCR2 中和抗体也消除了肌氨酸处理的 DC 在肿瘤模型中的生存获益。
肌氨酸通过 CXC 趋化因子途径增加鼠源和人源 DC 的迁移。该平台可用于改进现有的 DC 疫苗策略。
