PO.BCS01.04 · 生物信息与计算
空间单细胞转录组分析揭示 TIL/PD-L1 定义的 TNBC 亚型间不同的免疫和基质格局
Spatial single-cell transcriptomic profiling reveals distinct immune and stromal landscapes across TIL/PD-L1-defined TNBC subtypes
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
目的：
三阴性乳腺癌（TNBC）在免疫背景上表现出显著异质性，影响对免疫检查点阻断的反应。我们旨在利用单细胞空间转录组学，表征按肿瘤浸润淋巴细胞（TIL）和 PD-L1 表达分层的 TNBC 亚型之间的空间和细胞差异。
实验步骤：
我们使用 Xenium 平台（每个细胞约 5,000 个基因）分析了 36 个 TNBC 组织芯，并注释了主要细胞群体，包括上皮细胞、成纤维细胞和免疫细胞。基于组织学 TIL 密度（≥30%）和 PD-L1 CPS（≥10），将每个组织芯分为四种 TIL/PD-L1 亚型（TIL⁺PD-L1⁺、TIL⁺PD-L1⁻、TIL⁻PD-L1⁺ 和 TIL⁻PD-L1⁻）。在 50-μm 半径内计算肿瘤细胞与基质/免疫细胞之间的成对细胞间距离，以量化空间免疫排斥和基质重塑。
结果：
观察到各亚型之间存在不同的空间和转录谱。TIL⁺PD-L1⁺ 肿瘤表现出致密的免疫浸润，以及 CD4⁺ 和 CD8⁺ 亚群中抗原呈递和 T 细胞活化基因的上调。相比之下，TIL⁺PD-L1⁻ 肿瘤表现出显著的促纤维增生性基质和免疫细胞邻近度降低，并伴有成纤维细胞对 POSTN、FBLN1 和 SFRP2 的富集，提示细胞外基质重塑可能阻碍免疫浸润。TIL⁺PD-L1⁻ 组织芯中的上皮细胞表现出 XBP1、FOXA1 和 MLPH 的较高表达，提示上皮可塑性和潜在的免疫逃逸。空间定位进一步揭示，TIL⁺PD-L1⁻ 组织芯的肿瘤边缘比 TIL⁺PD-L1⁺ 肿瘤中相应的组织芯含有更具侵袭性的上皮表型。
结论：
单细胞空间转录组学勾勒出基于 TIL/PD-L1 的 TNBC 亚型间不同的免疫和基质结构。TIL⁺PD-L1⁺ 亚型代表一种免疫活跃的微环境，而 TIL⁺PD-L1⁻ 亚型则表现出基质驱动的免疫排斥。这些发现提供了空间证据，表明对 TIL 和 PD-L1 的联合评估可根据 TNBC 患者对免疫治疗的潜在反应性对其进行分层。
查看英文原文 English abstract
Purpose:
Triple-negative breast cancer (TNBC) displays marked heterogeneity in immune contexture, influencing response to immune checkpoint blockade. We aimed to characterize spatial and cellular differences among TNBC subtypes stratified by tumor-infiltrating lymphocytes (TILs) and PD-L1 expression using single-cell spatial transcriptomics.
Experimental Procedures:
We analyzed 36 TNBC cores using the Xenium platform (~5,000 genes per cell) and annotated major cell populations, including epithelial, fibroblast, and immune cells. Each core was classified into four TIL/PD-L1 subtypes (TIL⁺PD-L1⁺, TIL⁺PD-L1⁻, TIL⁻PD-L1⁺, and TIL⁻PD-L1⁻) based on histologic TIL density (≥30%) and PD-L1 CPS (≥10). Pairwise intercellular distances between tumor and stromal/immune cells were computed within a 50-μm radius to quantify spatial immune exclusion and stromal remodeling.
Results:
Distinct spatial and transcriptional profiles were observed among subtypes. TIL⁺PD-L1⁺ tumors exhibited dense immune infiltration and upregulation of antigen-presentation and T-cell activation genes in both CD4⁺ and CD8⁺ subsets. In contrast, TIL⁺PD-L1⁻ tumors showed prominent desmoplastic stroma and reduced immune-cell proximity, accompanied by fibroblast enrichment of POSTN , FBLN1 , and SFRP2 , suggesting extracellular-matrix remodeling that may hinder immune infiltration. Epithelial cells in TIL⁺PD-L1⁻ cores displayed higher expression of XBP1 , FOXA1 , and MLPH , indicating epithelial plasticity and potential immune evasion. Spatial mapping further revealed that tumor margins in TIL⁺PD-L1⁻ cores contained more aggressive epithelial phenotypes than corresponding cores in TIL⁺PD-L1⁺ tumors.
Conclusions:
Single-cell spatial transcriptomics delineated distinct immune and stromal architectures across TIL/PD-L1-based TNBC subtypes. The TIL⁺PD-L1⁺ subtype represents an immune-active microenvironment, whereas the TIL⁺PD-L1⁻ subtype demonstrates stromal-driven immune exclusion. These findings provide spatial evidence that combined assessment of TILs and PD-L1 can stratify TNBC patients by their potential responsiveness to immunotherapy.
利益披露 Disclosure
K. Kim, None..
Y. Cha, None..
A. Kim, None..
S. Ahn, None..
J. Jeong, None.