PO.IM01.11 · 免疫学
CD112通过鞘脂代谢依赖性重塑CD8+ T细胞受体格局并导致功能障碍，驱动HER2阳性乳腺癌的肿瘤免疫逃逸
CD112 drives tumor immune evasion in HER2-positive breast cancer through sphingolipid metabolism-dependent remodeling of CD8+T cell receptor landscapeand consequent dysfunction
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
目的：HER2阳性乳腺癌（HER2+BC）具有高TMB和丰富的TIL，支持免疫治疗潜力。HER2靶向治疗也调动免疫系统。然而，PD-1/PD-L1抑制剂显示疗效有限，提示该亚型存在独特的免疫抑制机制。
方法：对FUSCC和验证队列进行整合分析，鉴定关键免疫检查点。通过敲低候选免疫检查点和体内筛选进行实验验证。小鼠scRNA-seq揭示CD8+ T细胞为受损最严重的亚群。通过稳定细胞系和多组学分析表征CD112高表达肿瘤细胞，并通过空间转录组学验证。TurboID邻近标记鉴定出CD112-UGCG相互作用。使用条件培养基共培养和外源性GlcCer补充评估CD8+ T细胞功能。为证明CD112驱动的鞘脂代谢通过CD112-CD112R轴发挥功能，我们利用了Cd112r-KO小鼠。
结果：我们发现非pCR的HER2阳性患者具有相当水平的TIL，但表现出更耗竭的表型，并发现HER2靶向治疗后残余肿瘤中CD112显著上调。此外，虽然PD-L1在TNBC中高表达，但CD112在HER2+BC中显示特异性富集，主要定位于恶性上皮细胞。这些发现提示CD112在HER2+BC中可能具有更大的治疗潜力。除其经典的免疫抑制功能外，我们的研究揭示CD112促进鞘脂代谢，尤其是糖鞘脂。从机制上讲，通过TurboID我们发现了CD112与高尔基体中关键酶UGCG之间此前未报道的相互作用，该作用阻止UGCG降解，从而升高糖鞘脂水平。功能实验表明，CD112介导的对CD8+ T细胞的抑制部分依赖于其对鞘脂代谢的调节。通过改变外泌体膜的糖鞘脂含量，CD112高表达肿瘤细胞导致其关键受体CD112R在邻近CD8+ T细胞的脂筏中异常聚集，这增加了CD112-CD112R相互作用频率并放大了抑制效应。为进一步的体内转化，我们提出了抗HER2、抗CD112R和UGCG抑制剂的联合治疗。
结论：我们鉴定CD112为HER2+BC中一个关键的免疫抑制调节因子，超越PD-L1。我们还揭示了通过CD112-UGCG-GlcCer轴执行的CD112介导免疫抑制的代谢依赖性机制。抑制该轴可能进一步增强抗CD112R治疗在HER2+BC中的疗效，提出了一种有前景的联合策略。
查看英文原文 English abstract
Purpose: HER2-positive breast cancer (HER2+BC) features high TMB and abundant TILs, supporting immunotherapy potential. HER2-targeted therapies also engage the immune system. However, PD-1/PD-L1 inhibitors show limited efficacy, suggesting unique immunosuppressive mechanisms in this subtype.
Methods: Integrated analysis of FUSCC and validation cohorts identified key immune checkpoints. Experimental validation was performed through knockdown of candidate immune checkpoints and in vivo screening. Mouse scRNA-seq revealed CD8+ T cells as the most impaired subset. CD112-high tumor cells were characterized via stable cell lines and multi-omics analysis, with validation by spatial transcriptomics. TurboID proximity labeling identified CD112-UGCG interaction. CD8+ T cell function was assessed using conditioned medium co-culture and exogenous GlcCer supplementation. To demonstrate that CD112-driven sphingolipid metabolism exerts its function through CD112-CD112R axis, we utilized Cd112r-KO mice.
Results: We revealed that non-pCR HER2-positive patients have a comparable level of TILs but exhibited a more exhausted phenotype, and found significant upregulation of CD112 in residual tumors following HER2-targeted therapy. Moreover, while PD-L1 is highly expressed in TNBC, CD112 shows specific enrichment in HER2+BC, with predominant localization to malignant epithelial cells. These findings suggest that CD112 may hold greater therapeutic potential in HER2+BC. In addition to its canonical immunosuppressive function, our study revealed that CD112 promotes the metabolism of sphingolipid, particularly glycosphingolipid. Mechanistically, through TurboID we uncovered a previously unreported interaction between CD112 and the key enzyme UGCG in Golgi, which prevents UGCG degradation and thereby elevates glycosphingolipid level. Functional experiments demonstrated that CD112-mediated suppression of CD8+T cells is partially dependent on its regulation of sphingolipid metabolism. By altering the glycosphingolipid content of exosomal membranes, CD112-high tumor cells leads to the aberrant aggregation of CD112 key receptor-CD112R in lipid rafts of neighboring CD8+T cells, which increases CD112-CD112R interaction frequency and amplifies suppression effect. For furture in vivo translation, a combination therapy of anti-HER2, anti-CD112R, and a UGCG inhibitor is proposed.
Conclusion: We identified CD112 as a key immunosuppressive regulator in HER2+BC, surpassing PD-L1. We also revealed a metabolism-dependent mechanism of CD112-mediated immunosuppression executed through the CD112-UGCG-GlcCer axis. Inhibition of this axis may further enhances the efficacy of anti-CD112R treatment in HER2+BC, presenting a promising combination strategy.
利益披露 Disclosure
Y. Zhang, None..
B. Xiu, None..
J. Wu, None..
Q. Zhang, None.