通过上调溶酶体蛋白酶组织蛋白酶 S 增强人结直肠癌相关成纤维细胞中的抗原交叉呈递。
Enhanced antigen cross-presentation in human colorectal cancer-associated fibroblasts through upregulation of the lysosomal protease cathepsin S.
机构信息
Department of Gastroenterology and Hepatology, Leiden University Medical Center, Leiden, The Netherlands.
Department of Medical Oncology, Oncode Institute, Leiden University Medical Center, Leiden, The Netherlands.
出版信息
J Immunother Cancer. 2022 Mar;10(3). doi: 10.1136/jitc-2021-003591.
BACKGROUND
Cross-presentation of exogenous antigens in HLA-class I molecules by professional antigen presenting cells (APCs) is crucial for CD8+ T cell function. Recent murine studies show that several non-professional APCs, including cancer-associated fibroblasts (CAFs) also possess this capacity. Whether human CAFs are able to cross-present exogenous antigen, which molecular pathways are involved in this process and how this ultimately affects tumor-specific CD8+ T cell function is unknown.
METHODS
In this study, we investigated the ability of human colorectal cancer (CRC)-derived CAFs to cross-present neoantigen-derived synthetic long peptides (SLPs), corresponding to tumor-derived mutant peptides, and how this affects tumor-specific T-cell function. Processing of the SLP was studied by targeting components of the cross-presentation machinery through CRISPR/Cas9 and siRNA-mediated genetic ablation to identify the key molecules involved in fibroblast-mediated cross-presentation. Multispectral flow cytometry and killing assays were performed to study the effect of fibroblast cross-presentation on T cell function.
RESULTS
Here, we show that human CRC-derived CAFs display an enhanced capacity to cross-present neoantigen-derived SLPs when compared with normal colonic fibroblasts. Cross-presentation of antigens by fibroblasts involved the lysosomal protease cathepsin S. Cathepsin S expression by CAFs was detected in situ in human CRC tissue, was upregulated in ex vivo cultured CRC-derived CAFs and showed increased expression in normal fibroblasts after exposure to CRC-conditioned medium. Cognate interaction between CD8+ T cells and cross-presenting CAFs suppressed T cell function, reflected by decreased cytotoxicity, reduced activation (CD137) and increased exhaustion (TIM3, LAG3 and CD39) marker expression.
CONCLUSION
These data indicate that CAFs may directly suppress tumor-specific T cell function in an antigen-dependent fashion in human CRC.
背景
专业抗原呈递细胞 (APC) 中外源抗原在 HLA 类 I 分子中的交叉呈递对于 CD8+T 细胞功能至关重要。最近的鼠类研究表明，几种非专业 APC，包括癌相关成纤维细胞 (CAFs)，也具有这种能力。人类 CAFs 是否能够交叉呈递外源性抗原，该过程涉及哪些分子途径，以及这最终如何影响肿瘤特异性 CD8+T 细胞功能尚不清楚。
方法
在这项研究中，我们研究了人类结直肠癌 (CRC) 衍生的 CAFs 交叉呈递新抗原衍生的合成长肽 (SLP) 的能力，这些 SLP 对应于肿瘤衍生的突变肽，以及这如何影响肿瘤特异性 T 细胞功能。通过靶向交叉呈递机制的成分进行 CRISPR/Cas9 和 siRNA 介导的遗传消融来研究 SLP 的加工，以鉴定参与成纤维细胞介导的交叉呈递的关键分子。通过多光谱流式细胞术和杀伤测定来研究成纤维细胞交叉呈递对 T 细胞功能的影响。
结果
在这里，我们表明与正常结肠成纤维细胞相比，人类 CRC 衍生的 CAFs 显示出增强的交叉呈递新抗原衍生 SLP 的能力。成纤维细胞的抗原交叉呈递涉及溶酶体蛋白酶组织蛋白酶 S。在人类 CRC 组织中检测到原位 CAFs 中的组织蛋白酶 S 表达，在体外培养的 CRC 衍生 CAFs 中上调，并在暴露于 CRC 条件培养基后在正常成纤维细胞中表达增加。CD8+T 细胞与交叉呈递 CAFs 的同源相互作用抑制了 T 细胞功能，表现为细胞毒性降低、激活（CD137）减少和耗竭标志物（TIM3、LAG3 和 CD39）表达增加。
结论
这些数据表明，CAFs 可能以抗原依赖的方式直接抑制人类 CRC 中的肿瘤特异性 T 细胞功能。
Zotero 插件