OBJECTIVES The accumulation of tumor-associated macrophages (TAMs) is correlated with poor clinical outcome, but the mechanisms governing their differentiation from circulating monocytes remain unclear in humans. METHODS Using multicolor flow cytometry, we evaluated TAMs phenotype in 93 breast cancer (BC) patients. Furthermore, monocytes from healthy donors were cultured in the presence of supernatants from dilacerated primary tumors to investigate their differentiation into macrophages (MΦ) in vitro. Additionally, we used transcriptomic analysis to evaluate BC patients' blood monocytes profiles. RESULTS We observed that high intra-tumor CD163-expressing TAM density is predictive of reduced survival in BC patients. In vitro, M-CSF, TGF-β and VEGF from primary tumor supernatants skewed the differentiation of healthy donor blood monocytes towards CD163highCD86lowIL-10high M2-like MΦ that strongly suppressed CD4+ T-cell expansion via PD-L1 and IL-10. In addition, blood monocytes from about 40% of BC patients displayed an altered response to in vitro stimulation, being refractory to type-1 MΦ (M1-MΦ) differentiation and secreting higher amounts of immunosuppressive, metastatic-related and angiogenic cytokines. Aside from showing that monocyte transcriptome is significantly altered by the presence of BC, we also demonstrated an overall metabolic de-activation in refractory monocytes of BC patients. In contrast, monocytes from sensitive BC patients undergoing normal M1-MΦ differentiation showed up-regulation of IFN-response genes and had no signs of metabolic alteration. CONCLUSION Altogether, our results suggest that systemic factors skew BC patient blood monocytes towards a pro-metastatic profile, resulting in the accumulation of further polarised CD163high TAMs resembling type-2 MΦ (M2-MΦ) in the local BC microenvironment. These data indicate that monitoring circulating monocytes in BC patients may provide an indication of early systemic alterations induced by cancer and, thus, be instrumental in the development of improved personalised immunotherapeutic interventions.

中文翻译：

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乳腺癌患者中 CD163+ 肿瘤相关巨噬细胞的积累反映了局部分化信号和单核细胞的系统性偏斜。

目的 肿瘤相关巨噬细胞 (TAM) 的积累与不良的临床结果相关，但在人类中控制它们与循环单核细胞分化的机制仍不清楚。方法 使用多色流式细胞仪，我们评估了 93 名乳腺癌 (BC) 患者的 TAM 表型。此外，来自健康供体的单核细胞在存在来自扩张的原发性肿瘤的上清液的情况下进行培养，以研究它们在体外向巨噬细胞 (MΦ) 的分化。此外，我们使用转录组分析来评估 BC 患者的血液单核细胞谱。结果 我们观察到肿瘤内高表达 CD163 的 TAM 密度可预测 BC 患者的存活率降低。在体外，M-CSF，来自原发性肿瘤上清液的 TGF-β 和 VEGF 使健康供血单核细胞向 CD163highCD86lowIL-10high M2 样 MΦ 的分化倾斜，通过 PD-L1 和 IL-10 强烈抑制 CD4+ T 细胞扩增。此外，大约 40% 的 BC 患者的血液单核细胞对体外刺激的反应发生了改变，对 1 型 MΦ (M1-MΦ) 分化具有抵抗力，并分泌更多的免疫抑制、转移相关和血管生成细胞因子。除了表明单核细胞转录组因 BC 的存在而显着改变外，我们还证明了 BC 患者难治性单核细胞的整体代谢失活。相比之下，来自接受正常 M1-MΦ 分化的敏感 BC 患者的单核细胞显示出 IFN 反应基因的上调，并且没有代谢改变的迹象。结论 总而言之，我们的结果表明，全身因素使 BC 患者血液单核细胞倾向于前转移谱，导致进一步极化的 CD163high TAM 在局部 BC 微环境中积累，类似于 2 型 MΦ (M2-MΦ)。这些数据表明，监测 BC 患者的循环单核细胞可以提供癌症诱导的早期全身性改变的指示，因此有助于开发改进的个性化免疫治疗干预措施。