Neutrophils physically interact with tumor cells to form a signaling niche promoting breast cancer aggressiveness

Tissue remodeling and cell plasticity in the mammary gland are activated by multi-lineage communications. However, the dynamic signaling promoting breast cancer remains unclear. Here, by RNA-sequencing of single cells and physically interacting cells (PIC-seq) along mammary gland development and carcinogenesis, we uncovered that neutrophils appear transiently during early development and re-emerge in physical interaction with tumor cells in advanced carcinoma. Neutrophil heterogeneity analysis characterized transcriptional states linked to age and cancer stage. Integrating ligand-receptor and PIC-seq analyses with various functional experiments unveiled a physical and secreted pro-tumorigenic signaling niche. This approach revealed that neutrophils are recruited by ductal macrophages and physically interact with tumor cells, increasing tumor cell proliferative and invasive properties, as well as endothelial proliferation and angiogenesis. The molecular program upregulated in neutrophil-PICs correlates with lower survival in advanced breast cancer patients. Our interaction-driven perspective highlights potential molecular targets and biomarkers for breast cancer treatment. Transcriptional profiling of single cells and doublets (PIC) of of immune, non-immune and epithelial populations along different timepoints across mammary gland development and carcinogenesis

乳腺组织的组织重塑（tissue remodeling）与细胞可塑性（cell plasticity）可通过多谱系通讯（multi-lineage communications）激活。然而，介导乳腺癌发生发展的动态信号调控机制仍未明确。本研究针对乳腺发育与癌变进程中的单细胞及物理互作细胞测序（physically interacting cells sequencing, PIC-seq）开展RNA测序，发现中性粒细胞在发育早期一过性出现，并在晚期癌阶段重新与肿瘤细胞形成物理互作。中性粒细胞异质性分析明确了其转录状态与年龄及癌症分期的关联。整合配体-受体分析、PIC-seq分析与多种功能实验，本研究揭示了一个兼具物理互作与分泌功能的促肿瘤信号微环境。该研究发现，中性粒细胞由导管巨噬细胞招募而来，并与肿瘤细胞形成物理互作，进而增强肿瘤细胞的增殖与侵袭能力，同时促进内皮细胞增殖与血管生成（angiogenesis）。中性粒细胞-PICs中上调的分子程序与晚期乳腺癌患者的不良生存率显著相关。本研究基于互作驱动的研究视角，为乳腺癌治疗提供了潜在的分子靶点与生物标志物。本数据集涵盖乳腺发育与癌变进程中不同时间节点下，免疫细胞、非免疫细胞及上皮细胞群的单细胞与双细胞（doublets, PIC）转录组谱数据。