PO.TB10.11 · 肿瘤生物学
非达霉素靶向 PDGFR⁺ 癌症相关成纤维细胞以抑制结直肠癌进展
Fidaxomicin targets PDGFR⁺ cancer-associated fibroblast to restrain colorectal cancer progression
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
背景：结直肠癌（CRC）具有基质丰富的免疫抑制性肿瘤微环境（TME），其中活化的成纤维细胞驱动肿瘤进展并与不良预后相关。PDGFR⁺ 癌症相关成纤维细胞（CAFs）——包括 PDGFRalpha⁺ 炎症性 CAFs（iCAFs）和 PDGFRbeta⁺ 肌成纤维细胞样 CAFs（myCAFs）——在 CRC 中比例增高，并作为细胞间通讯的关键枢纽。高 PDGFR⁺ CAF 特征与不良结局相关。非达霉素是一种 FDA 批准的口服抗生素，可选择性清除致病性艰难梭菌，能抑制回肠纤维化并抑制肠道成纤维细胞中的 PDGFR 表达。本研究的目的是明确 PDGFR⁺ CAFs 促进 CRC 进展的机制，并评估非达霉素靶向 PDGFR 的抗肿瘤作用。
方法：我们对来自人类 CRC 及配对正常组织的数据集进行了基于 R 的分析，以比较细胞亚群比例、功能富集、细胞间通讯和虚拟细胞状态。使用 2D 和 3D 培养在体外、以及使用原位结肠癌模型（MC38 与 mCAF 细胞共植入）在体内评估了非达霉素对 CRC 细胞和 CAFs 增殖的影响。通过 3D 共培养、多色免疫荧光和流式细胞术检测了 CAF-中性粒细胞相互作用。
结果：单细胞转录组学数据集分析揭示，CRC 的 TME 中成纤维细胞显著活化，单核细胞-巨噬细胞和中性粒细胞群体增多。肿瘤富集的 CAF 亚群，包括 PDGFRalpha⁺ iCAFs 和 PDGFRbeta⁺ myCAFs，高水平表达 PDGFR 以及中性粒细胞趋化因子（如 CXCL1 和 CXCL14）。CAF 特征基因的 ssGSVA 评分与不良预后强相关。用非达霉素处理 CAFs 显著降低了 PDGFR 在 mRNA 和蛋白水平的表达，抑制了 STAT3 磷酸化，并下调了 CXCL1 和 CXCL14 转录。此外，口服非达霉素给药抑制了 MC38 肿瘤生长。在机制上，非达霉素抑制了 NOTCH-RBPJ-HDAC1/HDAC3 复合物的转录活性，导致 PDGFR 下调，并阻断了 PDGFR 介导的 STAT3 激活和核转位，而后者驱动 CXCL14 转录和免疫逃逸。
结论：我们的结果表明，PDGFR⁺ CAF 亚群在 CRC 进展中发挥关键作用。非达霉素破坏 PDGFR⁺ CAF-中性粒细胞相互作用，重塑 TME，并抑制肿瘤生长。重要的是，我们的发现提示，非达霉素具有良好的安全性且全身毒性极小，可能用于 CRC 治疗。
查看英文原文 English abstract
Background: Colorectal cancer (CRC) features a stroma-rich, immunosuppressive tumor microenvironment (TME) where activated fibroblasts drive tumor progression and correlate with poor prognosis. PDGFR⁺ cancer-associated fibroblasts (CAFs)-including PDGFRalpha⁺ inflammatory CAFs (iCAFs) and PDGFRbeta⁺ myofibroblastic CAFs (myCAFs)-are proportionally increased and serve as key hubs of intercellular communication in CRC. High PDGFR⁺ CAF signatures are associated with unfavorable outcomes. Fidaxomicin, an FDA-approved oral antibiotic which selectively eliminates pathogenic Clostridioides difficile , inhibits ileal fibrosis and suppresses PDGFR expression in intestinal fibroblasts. The purpose of this study was to define the mechanisms by which PDGFR⁺ CAFs promote CRC progression and to evaluate the anti-tumor effects of fidaxomicin targeting PDGFR.
Methods: We performed R-based analyses of datasets from human CRC and matched normal tissues to compare cellular subpopulation proportions, functional enrichment, cell-cell communication, and virtual cell states. Effects of fidaxomicin on the proliferation of CRC cells and CAFs were assessed in vitro using 2D and 3D cultures and in vivo using an orthotopic colon cancer model (MC38 co-implanted with mCAF cells). CAF-neutrophil interactions were examined through 3D co-culture, multicolor immunofluorescence, and flow cytometry.
Results: Analysis of datasets from single-cell transcriptomics revealed markedly activated fibroblasts and increased monocyte-macrophage and neutrophil populations within the TME of CRCs. Tumor-enriched CAF subsets, including PDGFRalpha⁺ iCAFs and PDGFRbeta⁺ myCAFs, expressed high levels of PDGFR and neutrophil-attracting chemokines such as CXCL1 and CXCL14. ssGSVA scores of CAF signature genes strongly correlated with poor prognosis. Treatment of CAFs with fidaxomicin significantly reduced PDGFR expression at both mRNA and protein levels, inhibited STAT3 phosphorylation, and downregulated CXCL1 and CXCL14 transcription. Moreover, oral fidaxomicin administration suppressed MC38 tumor growth. Mechanistically, fidaxomicin inhibited the transcriptional activity of the NOTCH-RBPJ-HDAC1/HDAC3 complex, leading to PDGFR downregulation and blocking PDGFR-mediated STAT3 activation and nuclear translocation that drives CXCL14 transcription and immune evasion.
Conclusions: Our results demonstrate that PDGFR⁺ CAF subsets play a critical role in CRC progression. Fidaxomicin disrupts PDGFR⁺ CAF-neutrophil interactions, remodels the TME, and inhibits tumor growth. Importantly, our findings suggest a potential usage of fidaxomicin, which maintains a favorable safety profile with minimal systemic toxicity, for CRC treatment.
利益披露 Disclosure
H. Zhang, None..
X. Zhu, None..
C. Li, None..
Y. Jiang, None..
Y. Zhou, None..
B. Evers, None..
Q. Wang, None.