CD73（ecto-5'-核苷酸酶，NT5E）是一种将 5'-AMP 转化为腺苷的细胞表面酶，对于癌症进展至关重要。然而，它在肿瘤发生过程中的作用仍然大多不清楚。我们的目的是通过脂肪酸代谢的代谢重新布线来证明 CD73 在乳腺癌 (BC) 肿瘤发生中的作用，最近表明这一过程受到 BC 主要预后标志物、雌激素 (ER) 和孕激素 (PR) 的激素受体 (HR) 的调节应用化学诱导乳腺肿瘤发生的小鼠模型来分析 CD73 敲除 (KO) 诱导的转录组 (RNA-seq)、蛋白质组 (IHC、WB) 和脂质组 (GC-EI-MS) 水平的变化。 CD73 KO 诱导的变化与来自公共收藏的人类乳腺组织和 BC 的 scRNA-seq 和批量 RNA-seq 数据相关，并通过 BC 组织微阵列和细胞系的 IHC 或 WB 分析在蛋白质组水平上得到证实。CD73 KO 延迟了发病小鼠模型中 HR/PR 阴性乳腺肿瘤的研究。这种延迟与CD73 KO组中起始阶段脂肪酸（FA）生物合成和β-氧化相关基因的表达增加相关。基于 RNA-seq 数据的 STRING 分析表明 CD73 KO、PR 编码基因表达上调和参与 FA 代谢的 DEG 之间存在相互作用，其中 PPARγ（FA 合成的主要调节因子）作为主要结缔节点。在乳腺上皮细胞中，PPARγ 表达在 RNA 水平上与 CD73 相关。随着癌症的进展，CD73 KO 增加了 PUFAn3/6（多不饱和 omega 3/6 FA）的水平，PUFAn3/6 是 PPARγ 的已知配体，也是脂质过氧化的靶标，可能导致 DNA 氧化损伤。它与参与细胞应激反应的基因（Mlh1、Gsta3）的下调、细胞内 ROS 水平的 PR 或 CD73 依赖性变化以及参与乳腺肿瘤或人类 BC 中 DNA 修复或氧化应激反应的蛋白质的表达或激活相关。 CD73 低 HR 阴性人类 BC 中肿瘤突变负荷 (TMB) 和基因组不稳定标记物增加，以及 CD73 KO HR/PR 阴性组肿瘤发病时间延长。CD73 在驱动重编程的肿瘤发生中具有重要作用通过乳腺上皮细胞中 PR 和 PPARγ 的调节环路来调节脂质代谢。低 CD73 表达/CD73 KO 可能会通过破坏这一调节环来增加突变负担，从而延迟 HR 阴性肿瘤的发生。我们的结果支持针对 HR 阴性肿瘤的针对 CD73-腺苷轴和肿瘤脂质组的联合治疗，特别是在其最早的发育阶段。版权所有 © 2024 作者。由 Elsevier GmbH 出版。保留所有权利。

CD73 (ecto-5'-nucleotidase, NT5E), a cell-surface enzyme converting 5'-AMP to adenosine, is crucial for cancer progression. However, its role in the tumorigenesis process remains mostly obscure. We aimed to demonstrate CD73's role in breast cancer (BC) tumorigenesis through metabolic rewiring of fatty acid metabolism, a process recently indicated to be regulated by BC major prognostic markers, hormone receptors (HR) for estrogen (ER), and progesterone (PR).A murine model of chemically induced mammary gland tumorigenesis was applied to analyze CD73 knock-out (KO)-induced changes at the transcriptome (RNA-seq), proteome (IHC, WB), and lipidome (GC-EI-MS) levels. CD73 KO-induced changes were correlated with scRNA-seq and bulk RNA-seq data for human breast tissues and BCs from public collections and confirmed at the proteome level with IHC or WB analysis of BC tissue microarrays and cell lines.CD73 KO delayed the onset of HR/PR-negative mammary tumors in a murine model. This delay correlated with increased expression of genes related to biosynthesis and β-oxidation of fatty acids (FAs) in the CD73 KO group at the initiation stage. STRING analysis based on RNA-seq data indicated an interplay between CD73 KO, up-regulated expression of PR-coding gene, and DEGs involved in FA metabolism, with PPARγ, a main regulator of FA synthesis, as a main connective node. In epithelial cells of mammary glands, PPARγ expression correlated with CD73 at the RNA level. With cancer progression, CD73 KO increased the levels of PUFAn3/6 (polyunsaturated omega 3/6 FAs), known ligands of PPARγ and target for lipid peroxidation, which may lead to oxidative DNA damage. It correlated with the downregulation of genes involved in cellular stress response (Mlh1, Gsta3), PR-or CD73-dependent changes in the intracellular ROS levels and expression or activation of proteins involved in DNA repair or oxidative stress response in mammary tumor or human BC cell lines, increased tumor mutational burden (TMB) and genomic instability markers in CD73 low HR-negative human BCs, and the prolonged onset of tumors in the CD73 KO HR/PR-negative group.CD73 has a significant role in tumorigenesis driving the reprogramming of lipid metabolism through the regulatory loop with PR and PPARγ in epithelial cells of mammary glands. Low CD73 expression/CD73 KO might enhance mutational burden by disrupting this regulatory loop, delaying the onset of HR-negative tumors. Our results support combining therapy targeting the CD73-adenosine axis and tumor lipidome against HR-negative tumors, especially at their earliest developmental stage.Copyright © 2024 The Authors. Published by Elsevier GmbH.. All rights reserved.