Department of Cardiothoracic Surgery, Zhangzhou Affiliated Hospital of Fujian Medical University, No. 59, Shengli West Road, Xiangcheng District, Zhangzhou City, 363000, Fujian Province, China.
Immunol Res. 2024 Aug;72(4):766-775. doi: 10.1007/s12026-024-09482-9. Epub 2024 Apr 30.
Esophageal cancer (EC) is the 9th most frequently diagnosed malignancy globally with unfavorable prognosis. Immune escape is one of the principal factors leading to poor survival, however, the mechanism underlying immune escape remains largely uninvestigated. The xenograft mouse model and EC cell-CD8 cytotoxic T lymphocytes (CTLs) co-culture system were established. Immunohistochemistry, qRT-PCR or western blot were employed to detect the levels of long non-coding RNA (lncRNA) FOXP4-AS1, PD-L1, USP10 and other molecules. The abundance of T cells, cytokine production and cell apoptosis were monitored by flow cytometry. The viability of CTLs was assessed by Trypan blue staining. The binding between FOXP4-AS1 and USP10 was validated by RNA pull-down assay, and the interaction between USP10 and PD-L1, as well as the ubiquitination of PD-L1, were detected by co-immunoprecipitation. The elevation of FOXP4-AS1 in EC was associated with decreased CTL abundance, and upregulated PD-L1 facilitated CTL apoptosis in EC. FOXP4-AS1 accelerated EC tumor growth by decreasing the abundance of tumor infiltrating CTLs in vivo. FOXP4-AS1 inhibited the viability of CTLs and facilitated the cytotoxicity and exhaustion of CTLs. In Kyse 450 cell-CTL co-culture system, FOXP4-AS1 suppressed the viability and abundance of CTLs, and inhibited EC cell apoptosis via PD-L1. Mechanistically, FOXP4-AS1 regulated the ubiquitination of PD-L1 through deubiquitinating enzyme USP10. FOXP4-AS1 promoted CTL exhaustion and EC immune escape through USP10-stabilized PD-L1. HIGHLIGHTS: PD-L1 facilitated CD8 T cell apoptosis in EC. Upregulated FOXP4-AS1 promoted EC tumor growth by inhibiting the viability and facilitating the cytotoxicity and exhaustion of tumor infiltrating CD8 T cells. FOXP4-AS1 suppressed the viability and abundance of CD8 T cells through USP10-mediated deubiquitination of PD-L1.
食管癌（EC）是全球第 9 大常见恶性肿瘤，预后不良。免疫逃逸是导致不良生存的主要因素之一，但免疫逃逸的机制在很大程度上仍未得到研究。建立了异种移植小鼠模型和 EC 细胞与 CD8 细胞毒性 T 淋巴细胞（CTL）共培养系统。采用免疫组织化学、qRT-PCR 或 Western blot 检测长链非编码 RNA（lncRNA）FOXP4-AS1、PD-L1、USP10 等分子的水平。通过流式细胞术监测 T 细胞的丰度、细胞因子的产生和细胞凋亡。采用台盼蓝染色法评估 CTL 的活力。通过 RNA 下拉实验验证 FOXP4-AS1 与 USP10 的结合，通过共免疫沉淀检测 USP10 与 PD-L1 的相互作用以及 PD-L1 的泛素化。EC 中 FOXP4-AS1 的升高与 CTL 丰度的降低有关，上调的 PD-L1 促进 EC 中 CTL 的凋亡。FOXP4-AS1 通过减少体内肿瘤浸润 CTL 的丰度促进 EC 肿瘤生长。FOXP4-AS1 抑制 CTL 的活力，并促进 CTL 的细胞毒性和耗竭。在 Kyse 450 细胞-CTL 共培养系统中，FOXP4-AS1 抑制 CTL 的活力和丰度，并通过 PD-L1 抑制 EC 细胞凋亡。机制上，FOXP4-AS1 通过去泛素化酶 USP10 调节 PD-L1 的泛素化。FOXP4-AS1 通过 USP10 稳定的 PD-L1 促进 CTL 耗竭和 EC 免疫逃逸。要点：PD-L1 促进 EC 中 CD8 T 细胞凋亡。上调的 FOXP4-AS1 通过抑制肿瘤浸润 CD8 T 细胞的活力和促进其细胞毒性和耗竭来促进 EC 肿瘤生长。FOXP4-AS1 通过 USP10 介导的 PD-L1 去泛素化来抑制 CD8 T 细胞的活力和丰度。
