Chen Yong-Qiang, Man Zhong-Song, Zheng Lu, Zhang Yue, Zhao Cheng-Wen, Ma Yu-Ting, Zhou Juan, Wang Peng, Yu Yang, Gu Feng, Niu Guo-Ping
Department of Clinical Laboratory, Xuzhou Institute of Medical Science, Xuzhou Central Hospital, Xuzhou, Jiangsu Province 221009, China.
Department of General Surgery, Xuzhou Central Hospital, Xuzhou, Jiangsu Province 221009, China.
Clin Immunol. 2024 Apr;261:109925. doi: 10.1016/j.clim.2024.109925. Epub 2024 Feb 3.
Inflammatory factors are being recognized as critical modulators of host antitumor immunity in liver cancer. We have previously shown that tumor cell-released LC3B positive extracellular vesicles (LC3B EVs) are responsible for malignant progression by dampening antitumor immunity. However, the relationship between LC3B EVs and inflammatory factors in the regulation of the liver cancer microenvironment remains unclear.
Flow cytometry analyses were performed to examine the panel of 12 cytokines, the main source of positive cytokines, and plasma LC3B EVs carrying HSP90α in peripheral blood of liver cancer patients. We correlated the levels of plasma IL-6, IL-8 with LC3B EVs carrying HSP90α and with prognosis. In vitro culture of healthy donor leukocytes with liver cancer-derived LC3B EVs was performed to evaluate the potential effect of blocking HSP90α, IL-6 or IL-8 alone or in combination with PD-1 inhibitor on CD8 T cell function. We also investigated the potential associations of MAP1LC3B, HSP90AA1, IL6 or IL8 with immunotherapy efficacy using the TCGA databases.
In liver cancer patients, plasma IL-6 and IL-8 levels were significantly higher than in healthy controls and associated with poor clinical outcome. In peripheral blood, levels of plasma LC3B EVs carrying HSP90α were significantly elevated in HCC patients and positively associated with IL-6 and IL-8 levels, which are predominantly secreted by monocytes and neutrophils. Moreover, LC3B EVs from human liver cancer cells promoted the secretion of IL-6 and IL-8 by leukocytes through HSP90α. Besides, we show that the cytokines IL-6 and IL-8 secreted by LC3B EVs-induced leukocytes were involved in the inhibition of CD8 T-cell function, while blockade of the HSP90α on the LC3B EVs, IL-6, or IL-8 could enhance anti-PD-1-induced T cell reinvigoration. Finally, patients who received anti-PD-1/PD-L1 immunotherapy with high MAP1LC3B, HSP90AA1, IL6, or IL8 expression had a lower immunotherapy efficacy.
Our data suggest that liver cancer-derived LC3B EVs promote a pro-oncogenic inflammatory microenvironment by carrying membrane-bound HSP90α. Targeting HSP90α on the LC3B EVs, IL-6, or IL-8 may synergize with anti-PD-1 treatment to enhance the CD8 T-cell functions, which may provide novel combination strategies in the clinic for the treatment of liver cancer.
炎症因子被认为是肝癌宿主抗肿瘤免疫的关键调节因子。我们之前已经表明，肿瘤细胞释放的LC3B阳性细胞外囊泡（LC3B EVs）通过抑制抗肿瘤免疫来促进恶性进展。然而，LC3B EVs与炎症因子在肝癌微环境调节中的关系仍不清楚。
进行流式细胞术分析，以检测12种细胞因子、阳性细胞因子的主要来源，以及肝癌患者外周血中携带HSP90α的血浆LC3B EVs。我们将血浆IL-6、IL-8水平与携带HSP90α的LC3B EVs水平及预后进行关联分析。用肝癌来源的LC3B EVs对健康供体白细胞进行体外培养，以评估单独阻断HSP90α、IL-6或IL-8，或与PD-1抑制剂联合使用对CD8 T细胞功能的潜在影响。我们还使用TCGA数据库研究了MAP1LC3B、HSP90AA1、IL6或IL8与免疫治疗疗效的潜在关联。
在肝癌患者中，血浆IL-6和IL-8水平显著高于健康对照，且与不良临床结局相关。在肝癌患者外周血中，携带HSP90α的血浆LC3B EVs水平显著升高，且与IL-6和IL-8水平呈正相关，而IL-6和IL-8主要由单核细胞和中性粒细胞分泌。此外，人肝癌细胞来源的LC3B EVs通过HSP90α促进白细胞分泌IL-6和IL-8。此外，我们发现LC3B EVs诱导的白细胞分泌的细胞因子IL-6和IL-8参与了对CD8 T细胞功能的抑制，而阻断LC3B EVs、IL-6或IL-8上的HSP90α可增强抗PD-1诱导的T细胞恢复活力。最后，接受抗PD-1/PD-L1免疫治疗且MAP1LC3B、HSP90AA1、IL6或IL8表达高的患者免疫治疗疗效较低。
我们的数据表明，肝癌来源的LC3B EVs通过携带膜结合的HSP90α促进促癌炎症微环境的形成。靶向LC3B EVs、IL-6或IL-8上的HSP90α可能与抗PD-1治疗协同作用，增强CD8 T细胞功能，这可能为肝癌治疗提供新的临床联合策略。
