PO.TB05.01 · 肿瘤生物学
CAF亚群通过不同的MYCN依赖性和非依赖性机制促成肿瘤对化疗的耐药
Subpopulations of CAF contribute to chemotherapy resistance in tumors through different MYCN-dependent and independent mechanisms
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摘要 Abstract
中文摘要
癌症相关成纤维细胞（CAF）是神经母细胞瘤（NB）肿瘤微环境（TME）中最常见的非恶性细胞亚型之一。CAF与肿瘤相关巨噬细胞协作，在包括NB在内的许多癌症中促进治疗逃逸。CAF具有异质性，已根据特定的转录组特征描述了若干亚群。在近期工作中，我们通过单细胞（sc）RNA测序展示了人NB肿瘤中存在不同的CAF亚群，包括肌成纤维细胞（myCAF）、炎症性（i）CAF、分裂性（d）CAF和血管性（v）CAF。然而，由于分离CAF亚群存在困难，这些亚群的具体功能尚不完全清楚。在此，我们根据血小板衍生生长因子-β受体（PDGF-Rbeta）和CD29（整合素β1）的表达，通过流式细胞术从人NB肿瘤中分离并表征了两个CAF亚群。我们发现这些亚群在体外维持稳定表型（至少31天），从而可研究其特定功能。根据其基因和蛋白表达，PDGF-Rbeta+/CD29-细胞被鉴定为myCAF，CD29+/PDGF-Rbeta-细胞被鉴定为iCAF。myCAF分泌TGF-beta1并在NB细胞中激活TAK1/NF-κB信号通路，而iCAF分泌白细胞介素（IL）-6和IL-8并在NB中激活STAT3。我们发现这两个亚群都增强了对多柔比星和依托泊苷的耐药性，但通过不同的旁分泌机制。myCAF通过TGF-beta/TAK1/NF-κB信号通路增加多药耐药蛋白MRP1和MDR1的表达，而iCAF通过IL-6/STAT3信号通路增加抗凋亡蛋白BCL-xL和BCL2的表达。此外，myCAF还以MYCN依赖性机制在NB细胞中激活自分泌IL-6/STAT3通路。对人NB的多重免疫化学分析显示，在TME丰富的肿瘤中存在表达PDGF-Rbeta的myCAF和表达CD29的iCAF，但在TME贫乏的肿瘤中缺乏myCAF。我们的数据凸显了CAF亚型对耐药性贡献的差异，并指出CAF在治疗耐药性出现中可能起关键作用。
查看英文原文 English abstract
Cancer-associated fibroblasts (CAF) are among the most prevalent non-malignant cell subtypes in the tumor microenvironment (TME) of neuroblastoma (NB). CAF cooperate with tumor-associated macrophages to promote therapeutic escape in many cancers including NB. CAF are heterogeneous and several subpopulations have been described based on specific transcriptomic signatures. In recent work, we show by single cell (sc)RNA sequencing the presence of different subpopulations of CAF in human NB tumors, including myofibroblasts (myCAF), inflammatory (i)CAF, dividing (d)CAF and vascular (v)CAF. However, the specific functions of these sub-populations are not entirely known because of difficulties in isolating CAF subpopulations. Here, we have isolated by flow cytometry and characterized two subpopulations of CAF from human NB tumors based on their expression of the receptor for platelet-derived growth factor-beta (PDGF-Rbeta) and CD29 (Integrin beta1). We show that these sub-populations maintain a stable phenotype in vitro (for at least 31 days) allowing to study their specific function. According to their gene and protein expression, PDGF-Rbeta+/CD29- cells were identified as myCAF and CD29+/PDGF-Rbeta- cells as iCAF. myCAF secreted TGF-beta1 and activated a TAK1/NF-κB signalling pathway in NB cells, whereas iCAF secreted interleukin (IL)-6 and IL-8 and activated STAT3 in NB. We discovered that both subpopulations enhanced resistance to doxorubicin and etoposide but through different paracrine mechanisms. myCAF increased the expression of multi-drug resistance proteins MRP1 and MDR1 via a TGF-beta/TAK1/NF-κB signalling pathway, and iCAF increased the expression of anti-apoptotic proteins BCL-xL and BCL2 via an IL-6/STAT3 signalling pathway. Furthermore, myCAF also activated an autocrine IL-6/STAT3 pathway in NB cells in a MYCN-dependent mechanism. A multiplex immunochemistry analysis of human NB revealed the presence of myCAF expressing PDGF-Rbeta and iCAF expressing CD29 in TME-rich tumors but an absence of myCAF in TME-poor tumors. Our data highlights differences in the contribution of CAF subtypes to drug resistance and points to a potentially critical role of CAF in the emergence of therapeutic resistance.
利益披露 Disclosure
K. Louault, None..
L. Sarte, None..
L. D. Grossmann, None..
B. Pawel, None..
S. Asgharzadeh, None..
Y. A. DeClerck, None.