PO.MCB03.02 · 分子与细胞生物学
肿瘤相关巨噬细胞与胶质母细胞瘤细胞之间的CD99同嗜性信号传导调控免疫治疗应答
CD99 homophilic signaling between tumor-associated macrophages and glioblastoma cells regulates response to immunotherapy
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
背景：胶质母细胞瘤（GBM）以不可避免的复发和深度治疗抵抗为特征，尤其对免疫治疗抵抗，复发性疾病的有效选择仍极为有限。以肿瘤相关巨噬细胞（TAMs）为主导的免疫抑制性肿瘤微环境在削弱抗肿瘤免疫和维持治疗抵抗中发挥核心作用。然而，将GBM细胞与TAMs联系到肿瘤复发和治疗失败的接触依赖性信号机制仍未明确。
方法：我们整合了来自原发性和复发性GBM以及免疫治疗应答者和非应答者的公开scRNA-seq数据集，以绘制肿瘤-免疫细胞通讯图谱。分析了TCGA-GBM和两个CGGA队列（CGGA-693和CGGA-325）的批量转录组数据，以确定CD99表达与患者生存、信号通路激活和致癌标志基因特征的关联。使用空间转录组学评估CD99高表达肿瘤细胞与巨噬细胞的空间邻近性及局部信号活性。为进行实验验证，我们开展体外和体内研究，以评估CD99阻断是否增强抗肿瘤免疫治疗的疗效。
结果：单细胞通讯分析显示，巨噬细胞群体在复发性GBM和免疫治疗非应答者中富集并被转录激活，其中巨噬细胞与肿瘤细胞之间CD99同嗜性介导的相互作用在这些情境中特异性富集。在TCGA和CGGA队列中，CD99高表达与更差的总生存相关（TCGA-GBM，p = 0.017；CGGA-693，p = 0.047；CGGA-325，p = 0.0039），并与增强的JAK/STAT信号、更高的EMT通路评分以及TGF-beta、IL-10和M2相关基因特征的表达升高相关。空间转录组学证实CD99高表达肿瘤细胞优先与巨噬细胞相邻，且这些微环境显示出升高的JAK2/STAT3活性。在实验中，在模拟免疫治疗的条件下，CD99阻断降低了GBM细胞中的JAK2/STAT3信号和EMT标志物表达，降低了TGF-beta/IL-10分泌，并减少了共培养中巨噬细胞的M2极化。在小鼠模型中，将CD99抑制与抗PD-L1联合进一步抑制肿瘤生长，并减弱了共注射巨噬细胞的促肿瘤效应。
结论：这些发现提示GBM细胞与巨噬细胞之间的CD99同嗜性结合是驱动治疗抵抗的JAK2/STAT3-EMT-M2极化环路的关键放大因子。靶向CD99介导的肿瘤-巨噬细胞串扰可能是克服抵抗和改善GBM结局的一种有前景的策略。
查看英文原文 English abstract
Background: Glioblastoma (GBM) is characterized by inevitable recurrence and profound therapy resistance, particularly to immunotherapy, and effective options for recurrent disease remain extremely limited. An immunosuppressive tumor microenvironment dominated by tumor-associated macrophages (TAMs) plays a central role in attenuating antitumor immunity and sustaining therapy resistance. However, the contact-dependent signaling mechanisms linking GBM cells and TAMs to tumor recurrence and treatment failure remain poorly defined.
Methods: We integrated publicly available scRNA-seq datasets from primary and recurrent GBM, as well as from immunotherapy responders and non-responders to map tumor-immune cell communication. Bulk transcriptomic data from TCGA-GBM and two CGGA cohorts (CGGA-693 and CGGA-325) were analyzed to determine the association of CD99 expression with patient survival, activation of signaling pathways, and oncogenic hallmark gene signatures. Spatial transcriptomics were used to assess the spatial proximity of CD99-high tumor cells and macrophages and the local signaling activity. For experimental validation, we performed in vitro and in vivo studies to assess whether CD99 blockade enhances the efficacy of anti-tumor immunotherapy.
Results: Single-cell communication analysis revealed that macrophage populations were enriched and transcriptionally activated in recurrent GBM and immunotherapy non-responders, with CD99 homophilic-mediated interactions between macrophages and tumor cells specifically enriched in these settings. Across TCGA and CGGA cohorts, high CD99 expression was associated with worse overall survival (TCGA-GBM, p = 0.017; CGGA-693, p = 0.047; CGGA-325, p = 0.0039), enhanced JAK/STAT signaling, higher EMT pathway scores, and elevated expression of TGF-beta, IL-10, and M2-related gene signatures. Spatial transcriptomics confirmed that CD99-high tumor cells were preferentially neighbored by macrophages, and these niches displayed elevated JAK2/STAT3 activity. Experimentally, under immunotherapy-mimicking conditions, CD99 blockade reduced JAK2/STAT3 signaling and EMT marker expression in GBM cells, lowered TGF-beta/IL-10 secretion, and diminished M2 polarization of macrophages in co-culture. In mouse models, combining CD99 inhibition with anti-PD-L1 further suppressed tumor growth and attenuated the tumor-promoting effect of co-injected macrophages.
Conclusions: These findings suggest CD99 homophilic engagement between GBM cells and macrophages as a critical amplifier of a JAK2/STAT3-EMT-M2 polarization loop that drives therapy resistance. Targeting CD99-mediated tumor-macrophage crosstalk may represent a promising strategy to overcome resistance and improve outcomes in GBM.
利益披露 Disclosure
T. Jiang, None..
Z. Huang, None..
N. Li, None..
H. Sun, None..
T. Jiang, None.