Tumor-Initiating Stem Cells Fine-tune the Cell States of Neutrophils to Drive Cancer Relapse from Immunotherapy [GeoMx]

The highly heterogeneous and plastic nature of tumor-associated neutrophils (TANs) has been recognized, but how different cell states of TANs emerge, evolve, distribute, and impact cancer immunotherapy efficacy remains elusive. Using single-cell RNA sequencing, spatial transcriptomic analysis, and genetic manipulations, we show that, while anti-PDL1/CD40 agonist immunotherapy can reprogram TANs to gain strong anti-tumor activities in squamous cell carcinomas (SCCs), a subset of neutrophils residing at the tumor-stroma interface can preserve their immune-suppressive state. Importantly, we identified a group of Sox2Hi tumor-initiating stem cells (tSCs) at the tumor-stroma interface that can activate Fatty Acid Desaturase 1 (Fads1) and produce arachidonic acid (AA) to induce autocrine prostaglandin E2 signaling which can disrupt the interferon responses in neutrophils. Thus, through this interaction, tSCs fine-tunes the cell states of neutrophils, shapes neutrophil heterogeneity, and sculpts a protective micro-niche to drive cancer relapse following immunotherapy. Overall design: To profile the neutrophils at different regions in the TME and their responses to immunotherapies, we employed spatial transcriptomics analysis to determine the distribution patterns of neutrophil responses in the spontaneous mouse SCCs.