PO.TB10.03 · 肿瘤生物学
Loxl2驱动中性粒细胞介导的免疫逃逸及小鼠黑色素瘤对抗PD-1治疗的抵抗
Loxl2 drives neutrophil-mediated immune evasion and resistance to anti PD-1 therapy in murine melanoma
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
以抗PD-1（alphaPD-1）为代表的免疫检查点阻断（ICB）疗法彻底改变了黑色素瘤的治疗；然而，由于固有或适应性抵抗机制，反应率仍不理想。尽管已有大量工作聚焦于阐明抵抗机制和提高疗效，但肿瘤内表观遗传调控的作用仍未得到充分探索。对非应答黑色素瘤患者治疗前后样本的scRNA-seq和scATAC-seq分析显示，纳武利尤单抗（nivolumab）治疗后H3K4氧化酶LOXL2上调。LOXL2的表达富集于一个未被表征的肿瘤亚簇中，该亚簇不同于缺氧肿瘤簇和成纤维细胞簇。这些发现使我们假设LOXL2促成免疫逃逸并促进对alphaPD-1抵抗的肿瘤微环境。为验证这一点，我们在接受alphaPD-1治疗的小鼠皮下（SQ）黑色素瘤模型中评估了LOXL2敲低（KD）的影响。使用scRNA-seq对肿瘤进行分析，以评估细胞类型特异性的转录变化和免疫组成。LOXL2 KD显著改善了B6 SQ肿瘤中a-PD-1的疗效，减少了N2促肿瘤中性粒细胞并增加了细胞毒性CD8+ T细胞的浸润。为研究LOXL2如何影响肿瘤相关中性粒细胞（TAN）的极化，我们检测了LOXL2 KD后的表观基因组改变和下游基因调控。我们发现了SOCS1介导的NF-κB转录减弱，以及促炎细胞因子（即IL-1beta、TGFbeta）分泌的减少，这有利于N1而非N2极化。总的来说，我们的发现表明，LOXL2驱动的肿瘤分泌细胞因子，促进N2中性粒细胞极化，导致CD8+ T细胞排斥和对alphaPD-1治疗的抵抗。靶向LOXL2可能将肿瘤免疫微环境重编程为免疫应答状态，为增强黑色素瘤中的ICB反应提供潜在策略。
查看英文原文 English abstract
Immune checkpoint blockade (ICB) therapy with anti-PD-1 (alphaPD-1) has revolutionized melanoma treatment; however, response rates remain suboptimal due to innate or adaptive resistance mechanisms. Although substantial efforts have focused on enlightening resistance mechanism and improving the efficacy, the role of epigenetic regulation within tumor remains insufficiently explored.scRNA-seq and scATAC-seq analysis of pre- and post-treatment samples from non-responding melanoma patients revealed upregulation of H3K4 oxidase LOXL2 following nivolumab treatment. LOXL2 expression was enriched in an uncharacterized tumor subcluster, distinct from hypoxic tumor and fibroblast clusters. These findings led us to hypothesize that LOXL2 contributes to immune evasion and promotes alphaPD-1 resistant tumor microenvironment.To test this, we evaluated the impact of LOXL2 knockdown (KD) in a murine subcutaneous (SQ) melanoma model treated with alphaPD-1. Tumors were profiled using scRNA-seq to assess cell-type-specific transcriptional changes and immune composition. LOXL2 KD significantly improved a-PD-1 efficacy in B6 SQ tumors, reducing N2 pro-tumorigenic neutrophils and increasing cytotoxic CD8+ T cell infiltration.To investigate how LOXL2 influences tumor-associated neutrophils (TANs) polarization, we examined epigenomic alterations and downstream gene regulation upon LOXL2 KD. We identified SOCS1-mediated NF- κB transcriptional attenuation, along with reduced secretion of pro-inflammatory cytokines (i.e. IL-1beta, TGFbeta) which favors N1 rather than N2 polarization.Collectively, our findings suggest that LOXL2-driven tumors secrete cytokines that promote N2 neutrophil polarization, leading to CD8+ T cell exclusion and resistance to alphaPD-1 therapy. Targeting LOXL2 may reprogram the tumor immune microenvironment toward an immune-responsive state, offering a potential strategy to enhance ICB response in melanoma.
利益披露 Disclosure
J. Yang, None..
V. Kochat, None..
S. Satpati, None.