Liu Qiang, Chen Huiguo, Tang Dongfang, Zhang Huibiao, Chen Shaogeng, Meng Yiran, Zheng Boying, Liu Fei, Zhou Jing, Zhang Wen
Department of Thoracic Surgery, Peking University International Hospital, Beijing, China.
Department of Cardiothoracic Surgery, The Third Affiliated Hospital of Sun Yat - sen University, Guangzhou, Guangdong, China.
Front Pharmacol. 2025 May 22;16:1562261. doi: 10.3389/fphar.2025.1562261. eCollection 2025.
Tumor metabolism reprogramming is a hallmark of cancer, but metabolite-mediated intercellular communication remains poorly understood. To address this gap, we estimated and explored communication events exploring based on single-cell RNA data, to explore the metabolic landscape of tumor microenvironment (TME) in lung adenocarcinoma (LUAD) and identify novel metabolite signaling axis.
The scRNA-seq dataset was subjected to dimensionality reduction using the Seurat package. Cell annotation was manually performed using typical markers from Cell Marker 2.0 and previous studies. Single-cell metabolite abundance and communication events were inferred using MEBOCOST. The TCGA-LUAD datasets was used to estimate and analyze immune cell infiltration levels and tumor hot score using the ESTIMATE and ssGSEA algorithms. Additionally, survival analysis was conducted on genes within relative signaling axis. All analysis above in TCGA-LUAD dataset was validated by two Gene Expression Omnibus (GEO) datasets. The expression patterns of PTGDR and PTGDS were validated by RT-qPCR and fluorescence in situ hybridisation.
Five landmark metabolites across cell types were identified as prostaglandin D2 (PGD2), D-Mannose, Choline, L-Cysteine, and Cholesterol of TME in LUAD. Prostaglandin D2 (PGD2) emerged as a key player, primarily produced by fibroblasts and plasmacytoid dendritic cells (pDCs) by via the gene and by mast cells via the gene. PGD2 signaling was shown to primarily be received by the PGD2 receptor () on NK/T cells and transported by the transporter on endothelial cells. NK/T cells, which are prominent cytotoxic populations, as a PGD2 autocrine signaling axis, are involved in PGD2 autocrine signaling, while KLRC2+ NK, DNAJB1+ NK cells and CD8+ MAIT cells participate in PGD2 paracrine signaling. PGD2 may also assist lactate efflux via on endothelial cells. The clinical relevance of the PGD2 signaling axis was validated across multiple bulk RNA datasets, showing that it is associated with the infiltration of above immune cells such as DNAJB1+ NK cells, and linked to better prognosis in LUAD. Furthermore, we found that a risk model developed based on this signaling axis could predict responses to immune therapy in hot and cold tumors, suggesting potential drugs that may benefit low-risk patients. These findings were further supported by RT-qPCR and immunofluorescence data, which confirmed the downregulation of PTGDS and PTGDR in LUAD tumor tissues compared to normal tissues.
Collectively, these results suggest that PGD2 and its signaling axis play a significant role in tumor-suppressive and anti-inflammatory effects in LUAD, with potential applications in prognosis management and therapy decision-making.
肿瘤代谢重编程是癌症的一个标志，但代谢物介导的细胞间通讯仍知之甚少。为了填补这一空白，我们基于单细胞RNA数据估计并探索了通讯事件，以探究肺腺癌（LUAD）中肿瘤微环境（TME）的代谢格局，并识别新的代谢物信号轴。
使用Seurat软件包对scRNA-seq数据集进行降维处理。使用来自Cell Marker 2.0和先前研究的典型标志物进行细胞注释。使用MEBOCOST推断单细胞代谢物丰度和通讯事件。使用ESTIMATE和ssGSEA算法对TCGA-LUAD数据集进行免疫细胞浸润水平和肿瘤热评分的估计和分析。此外，对相关信号轴内的基因进行生存分析。上述在TCGA-LUAD数据集中的所有分析均通过两个基因表达综合数据库（GEO）数据集进行验证。通过RT-qPCR和荧光原位杂交验证PTGDR和PTGDS的表达模式。
在LUAD的TME中，跨细胞类型的五种标志性代谢物被鉴定为前列腺素D2（PGD2）、D-甘露糖、胆碱、L-半胱氨酸和胆固醇。前列腺素D2（PGD2）成为关键角色，主要由成纤维细胞和浆细胞样树突状细胞（pDC）通过 基因产生，肥大细胞通过 基因产生。PGD2信号主要由NK/T细胞上的PGD2受体（ ）接收，并由内皮细胞上的 转运体转运。作为PGD2自分泌信号轴的NK/T细胞是突出的细胞毒性群体，参与PGD2自分泌信号，而KLRC2+NK、DNAJB1+NK细胞和CD8+MAIT细胞参与PGD2旁分泌信号。PGD2还可能通过内皮细胞上的 协助乳酸外流。PGD2信号轴与多种批量RNA数据集的临床相关性得到验证，表明它与DNAJB1+NK细胞等上述免疫细胞的浸润相关，并与LUAD的较好预后相关。此外，我们发现基于该信号轴开发的风险模型可以预测冷热肿瘤对免疫治疗的反应，提示可能使低风险患者受益的潜在药物。RT-qPCR和免疫荧光数据进一步支持了这些发现，证实与正常组织相比，LUAD肿瘤组织中PTGDS和PTGDR下调。
总体而言，这些结果表明PGD2及其信号轴在LUAD的肿瘤抑制和抗炎作用中发挥重要作用，在预后管理和治疗决策中具有潜在应用价值。
