Abstract PR-08: Reprogramming and selective recruitment of distinct neutrophil subpopulations restrain cancer metastasis

Abstract Neutrophils are integral to the metastatic tumor microenvironment (TME), and discrete subsets of neutrophils have been associated with pro- and anti-tumor responses. However, the composition of neutrophils in the metastatic TME and strategies to harness neutrophils for the treatment of metastatic disease remain poorly understood. Here, we studied the role of neutrophils in metastatic disease using mouse models of metastatic pancreatic ductal adenocarcinoma (PDAC). By utilizing mouse PDAC cells driven by mutant KRAS and p53 with controllable expression of ovalbumin, an immunogenic antigen (“TumorAg ON” or “TumorAg OFF”), we found that TumorAg ON PDAC engendered more than 10-fold higher recruitment of neutrophils into liver metastatic lesions compared to TumorAg OFF PDAC. RNA sequencing analysis of micro-dissected metastatic lesions showed that TumorAg ON PDAC elicited transcription of genes associated with neutrophil chemotaxis, including Cxcr2 and its ligands. Multimodal immune phenotyping and imaging mass cytometry (IMC) analysis further revealed that neutrophils within metastatic lesions consisted of CXCR2high and CXCR2low subpopulations and were spatially associated with distinct subsets of tumor cells, T cells, and myeloid cells. In both mouse models of liver and lung metastasis, small molecule inhibition of CXCR2 using SX-682 led to enrichment of CXCR2low neutrophils and reduced metastatic burden in TumorAg ON PDAC. In contrast, CXCR2 inhibition had no impact on metastatic burden in TumorAg OFF PDAC. To define the subpopulations of neutrophils in further depth, we also performed single-cell spatial transcriptomics using Xenium. Notably, CXCR2 inhibition in TumorAg ON PDAC, but not in TumorAg OFF, led to enrichment of neutrophil subsets that expressed higher levels of Mpo, Nos2, and Ly6g and lower levels of Cxcr2 and Siglecf into metastatic lesions. In this setting, depletion of neutrophils using anti-Ly6G antibodies worsened metastatic burden, highlighting anti-tumor properties of these neutrophil subsets in the presence of antigenic recognition. Indeed, in a highly immune-resistant model of PDAC, 6419c5, the use of tumor-targeting listeria vaccine CRS-207 along with CXCR2 inhibition significantly reduced metastatic burden, whereas CXCR2 inhibitor or CRS-207 alone had no impact. To extend the clinical relevance of these observations, we analyzed serial tissue biopsies collected from patients with metastatic PDAC in the liver treated with immunotherapy regimen incorporating CRS-207 (NCT03190265). Consistent with our mouse model results, IMC analysis revealed increased proportion of MPOhigh NOS2high neutrophils upon treatment, suggesting that induction of tumor antigen response results in an effective remodeling of the neutrophil compartment. Taken together, our results show that neutrophils may acquire anti-tumor properties under appropriate inflammatory conditions and that distinct subpopulations of neutrophils may be leveraged for the treatment of metastatic disease. Citation Format: Jae W Lee, Diana Caroline Vargas Carvajal, Yeonju Cho, Sarah M Shin, Erin M Coyne, Alexei Hernandez, Courtney D Cannon, Xuan Yuan, Zhehao Zhang, Nicole E Gross, Soren Charmsaz, Daniel H Shu, Katherine M Bever, Dung T Le, Luciane T Kagohara, Elizabeth M Jaffee, Won Jin Ho. Reprogramming and selective recruitment of distinct neutrophil subpopulations restrain cancer metastasis abstract. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84 (17 Suppl₂): Abstract nr PR-08.