Neuromedin U (NMU) was identified as one of the hub genes closely related to colorectal cancer (CRC) progression and was recently shown to be a motility inducer in CRC cells. Its autocrine signalling through specific receptors increases cancer cell migration and invasiveness. Because of insufficient knowledge concerning NMU accessibility and action in the tumour microenvironment, its role in CRC remains poorly understood and its potential as a therapeutic target is still difficult to define. NMU expression in CRC tissue was detected by IHC. Data from The Cancer Genome Atlas were used to analyse gene expression in CRC. mRNA and protein expression was detected by real-time PCR, immunoblotting or immunofluorescence staining and analysed using confocal microscopy or flow cytometry. Proteome Profiler was used to detect changes in the profiles of cytokines released by cells constituting tumour microenvironment after NMU treatment. NMU receptor activity was monitored by detecting ERK1/2 activation. Transwell cell migration, wound healing assay and microtube formation assay were used to evaluate the effects of NMU on the migration of cancer cells, human macrophages and endothelial cells. Our current study showed increased NMU levels in human CRC when compared to normal adjacent tissue. We detected a correlation between high NMUR1 expression and shorter overall survival of patients with CRC. We identified NMUR1 expression on macrophages, endothelial cells, platelets, and NMUR1 presence in platelet microparticles. We confirmed ERK1/2 activation by treatment of macrophages and endothelial cells with NMU, which induced pro-metastatic phenotypes of analysed cells and changed their secretome. Finally, we showed that NMU-stimulated macrophages increased the migratory potential of CRC cells. We propose that NMU is involved in the modulation and promotion of the pro-metastatic tumour microenvironment in CRC through the activation of cancer cells and other tumour niche cells, macrophages and endothelial cells.

中文翻译：

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结直肠癌细胞分泌的神经调节素 U 促进肿瘤支持微环境

Neuromedin U (NMU) 被确定为与结直肠癌 (CRC) 进展密切相关的中枢基因之一，最近被证明是 CRC 细胞中的运动诱导剂。其通过特定受体的自分泌信号增加了癌细胞的迁移和侵袭性。由于对 NMU 可及性和在肿瘤微环境中的作用了解不足，对其在 CRC 中的作用仍知之甚少，其作为治疗靶点的潜力仍难以界定。IHC检测CRC组织中的NMU表达。来自癌症基因组图谱的数据用于分析 CRC 中的基因表达。通过实时 PCR、免疫印迹或免疫荧光染色检测 mRNA 和蛋白质表达，并使用共聚焦显微镜或流式细胞术进行分析。Proteome Profiler 用于检测 NMU 处理后构成肿瘤微环境的细胞释放的细胞因子谱的变化。通过检测 ERK1/2 激活来监测 NMU 受体活性。Transwell 细胞迁移、伤口愈合试验和微管形成试验用于评估 NMU 对癌细胞、人巨噬细胞和内皮细胞迁移的影响。我们目前的研究表明，与正常的邻近组织相比，人类 CRC 中的 NMU 水平有所增加。我们检测到高 NMUR1 表达与 CRC 患者较短的总生存期之间存在相关性。我们确定了 NMUR1 在巨噬细胞、内皮细胞、血小板上的表达，以及 NMUR1 在血小板微粒中的存在。我们通过用 NMU 处理巨噬细胞和内皮细胞证实了 ERK1/2 激活，它诱导了分析细胞的促转移表型并改变了它们的分泌蛋白组。最后，我们发现 NMU 刺激的巨噬细胞增加了 CRC 细胞的迁移潜力。我们提出 NMU 通过激活癌细胞和其他肿瘤生态位细胞、巨噬细胞和内皮细胞参与调节和促进 CRC 中的促转移肿瘤微环境。