Neurotrophic receptor GFRα2 drives pro-metastatic programming of Kupffer cells in liver metastases 2257034

Abstract Introduction Gastrointestinal cancers such as colorectal and pancreatic cancers frequently metastasize to the liver, contributing significantly to cancer-related mortality and resistance to immune checkpoint inhibitors. Recent multidisciplinary studies have highlighted a functional and mechanistic interplay between nervous and immune systems in cancers, termed as neuroimmune axis. Besides, liver is known to have rich innervation. Therefore, targeting neuroimmune regulatory molecules on immune cells to facilitate liver metastasis treatment is possible. Methods Our study employed analysis of public available single-cell omics datasets from patients and donors. Single-cell sequencing, high-dimensional flow cytometry and multiplex-immunofluorescence analysis in mice and patients with liver metastasis were also applied in this study. Results Glial cell line-derived neurotrophic factor (GDNF) family receptor alpha 2 (GFRα2) was found to have elevated expression on colorectal cancer liver metastasis (CRLM) adjacent livers compared with healthy livers. It was further confirmed that GFRα2 was selectively expressed and was upregulated on Timd4+Clec4f+Kupffer cells (KCs). Notably, GFRα2+KCs were found in close proximity to liver-infiltrating nerve fibers in CRLM, whereas chemical liver denervation led to reduced expression of GFRα2, suggesting a possible neural regulation on GFRα2+KCs. Functionally, lentiviral shRNA-mediated Gfra2 knockdown significantly suppressed liver metastasis without affecting primary colorectal tumor growth, which was abolished by KCs depletion. Mechanistically, GFRα2+KCs displayed impaired antigen presentation capacity, but enhanced pro-angiogenesis and neutrophil recruitment, suggesting a reprogrammed, metastasis-promoting phenotype. Gfra2 knockdown significantly reduced neutrophil accumulation and angiogenesis, but increased MHCII+KCs. Conclusion Taken together, our findings pinpointed that GFRα2 upregulation reprograms KCs towards a pro-metastatic state, thereby facilitate liver metastasis. Funding Source This project is supported by the Hong Kong University Grants Committee through the General Research Fund (14107622, 24110323) and the Strategic Seed Funding for Collaborative Research Scheme (SSFCRS) from the Chinese University of Hong Kong. Topic Categories Tumor Immunology: Checkpoints, Prevention, and Treatment (TIPT)