Determining the role of neutrophils in anti-tumor immunity and immune-related adverse events in the context of T cell-based therapies - PROJECT SUMMARY/ABSTRACT Despite recent progress, most patients with solid tumors still do not respond to immunotherapies. Responders often experience immune-related adverse events (irAEs), which can be life-threatening and require treatment discontinuation. Current immunotherapies focus on enhancing the fitness of anti-tumor effector T cells, but do not simultaneously engage innate immune responses. Neutrophils infiltrate tumors and can exhibit either anti- or pro-tumorigenic properties, depending on the context of tissue inflammation. While chronic inflammation favors pro-tumorigenic neutrophils, we and others have demonstrated that acute inflammation induced by T cell therapies promotes anti-tumorigenic neutrophils that help eradicate the tumor. However, it remains unclear how neutrophils become tumoricidal following immunotherapy. In melanoma, neutrophils also infiltrate healthy tissues of immunotherapy-responders with irAEs, suggesting potential pathogenic properties. Nonetheless, the direct contribution of neutrophils to development of irAEs has not been addressed. Understanding these mechanisms is crucial to develop new combination treatments that activate synergies between the innate and adaptive immune systems to potentiate anti-tumor responses while preventing immunological toxicities. To investigate the precise role of neutrophils in anti-tumor immunity and irAEs, we propose: Aim 1. Characterize gene pathways and tumor-derived factors defining functional subsets of anti-tumorigenic neutrophils. We will identify key molecular targets underlying neutrophil tumoricidal activity by integrating scRNA- seq and proteomics across models of anti- and pro-tumorigenic neutrophils. We will evaluate whether these targets can promote neutrophil-mediated tumor control in preclinical melanoma and breast cancer models. Aim 2. Identify clinically relevant mechanisms of tumor cell destruction employed by neutrophils. We will evaluate the contribution of known neutrophil killing pathways, including ROS and NETosis, to immunotherapies using genetic models and inhibitors targeting key mediators of these pathways. We will assess if neutrophils selectively kill tumor cells. Furthermore, we will evaluate the clinical relevance of gene signatures, molecular cues, and killing mechanisms in biospecimens from patients with solid tumors undergoing immunotherapies. Aim 3. Uncover the role of neutrophils in development of irAEs. Preliminary data suggest that neutrophil depletion alleviates skin immunological toxicities associated with immunotherapy. We will use this model along with scRNA-seq studies to identify actionable targets that uncouple neutrophil tumoricidal activity from pathogenic behavior and validate findings in patient samples. We will also evaluate the contribution of VISTA and NETosis to development of irAEs. We expect to find immunotherapeutic interventions based on innate immune profiles and reliable biomarkers for cancer prognosis. Our long-term goal is to develop approaches targeting neutrophils that enhance anti-tumor immunity while preventing associated toxicities to advance the precision and safety of immunotherapies.
