Investigating how the metastatic niche impairs NK cell cytotoxicity in early lung metastasis from breast cancer

自然杀伤(NK)细胞是乳腺癌肿瘤微环境中具有重要抗癌功能的天然淋巴细胞。虽然NK细胞有能力清除转移部位的播散性癌细胞，但它们的细胞毒活性在成功转移时会受到损害。我们假设TME中的其他成分在转移定植的早期阶段抑制NK细胞的激活并起到对抗癌细胞的作用。因此，我们使用了体内标记工具Cherry-Niche来描述乳腺癌肺微转移中TME细胞的变化和相互作用。我们的单细胞RNA测序(scRNA-seq)分析确定了成纤维细胞和单核细胞亚群，这些亚群富含转移的小生境和NK细胞的活跃信号。接下来，我们开发了2D和3D共培养系统来研究NK细胞、成纤维细胞和单核细胞之间的串扰。我们目前正在使用这些系统来测试NK细胞和成纤维细胞/单核细胞之间选定的分子相互作用的作用，这些作用是我们使用生物信息学工具，如CellChat和NicheNet在计算机中确定的。这项研究将揭示在转移的生态位中发生的新的细胞间动力学，以及可能恢复早期转移的NK细胞杀伤作用的具有免疫治疗潜力的分子靶点。

Natural killer (NK) cells are innate lymphocytes with important anti-cancer functions in the tumour microenvironment (TME) of breast cancer. Although NK cells have the capacity to eliminate disseminated cancer cells at the metastatic site, their cytotoxic activity is impaired in successful metastasis. We hypothesise that other components within the TME inhibit NK cell activation and function against cancer cells at the early stage of metastatic colonisation. Therefore, we have used Cherry-niche, an in vivo labelling tool, to characterise how TME cells change and interact with each other in lung micro-metastases from breast cancer. Our single-cell RNA sequencing (scRNA-seq) analysis identified subpopulations of fibroblasts and monocytes that are enriched in the metastatic niche and active signallers to NK cells. Next, we have developed 2D and 3D co-culture systems to study the crosstalk between NK cells, fibroblasts and monocytes. We are currently using these systems to test the role of selected molecular interactions between NK cells and fibroblasts/monocytes that we identified in silico using bioinformatic tools, such as CellChat and NicheNet. This study will reveal novel inter-cellular dynamics occurring in the metastatic niche, as well as molecular targets that may restore NK cell cytotoxicity in early metastasis with immunotherapeutic potential.