Sheena Suthen1, Chun Jye Lim1, Phuong H D Nguyen1, Charles-Antoine Dutertre2,3, Hannah L H Lai4, Martin Wasser1, Camillus Chua1, Tony K H Lim5,6, Wei Qiang Leow5,6, Tracy Jiezhen Loh5,6, Wei Keat Wan5,6, Yin Huei Pang7, Gwyneth Soon7, Peng Chung Cheow5,8, Juinn Huar Kam5,8, Shridhar Iyer9, Alfred Kow9, Wai Leong Tam4,10,11,12, Timothy W H Shuen13, Han Chong Toh5,13, Yock Young Dan14, Glenn K Bonney9, Chung Yip Chan5,8, Alexander Chung5,8, Brian K P Goh5,8, Weiwei Zhai2,15,16, Florent Ginhoux2,3, Pierce K H Chow8,17, Salvatore Albani1, Valerie Chew1. 1. Translational Immunology Institute, SingHealth Duke-NUS Academic Medical Center, Singapore. 2. Gustave Roussy Cancer Campus, Villejuif, France. 3. Institut National de la Santé Et de la Recherche Médicale (INSERM) U1015, Equipe Labellisée-Ligue Nationale Contre le Cancer, Villejuif, France. 4. Agency for Science, Technology and Research, Genome Institute of Singapore, Singapore. 5. Duke-NUS Medical School, Singapore. 6. Department of Anatomical Pathology, Singapore General Hospital, Singapore. 7. Department of Pathology, National University Hospital, Singapore. 8. Division of Surgery and Surgical Oncology, Department of Hepatopancreatobiliary and Transplant Surgery, Singapore General Hospital and National Cancer Center Singapore, Singapore. 9. Division of Hepatobiliary and Pancreatic Surgery, Department of Surgery, University Surgical Cluster, National University Health System, Singapore. 10. School of Biological Sciences, Nanyang Technological University, Singapore. 11. Cancer Science Institute of Singapore, National University of Singapore, Singapore. 12. Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore. 13. Division of Medical Oncology, National Cancer Center Singapore, Singapore. 14. Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore. 15. Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China. 16. Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming, China. 17. Academic Clinical Programme for Surgery, SingHealth Duke-NUS Academic Medical Centre, Singapore.
Abstract
BACKGROUND AND AIMS: Hypoxia is one of the central players in shaping the immune context of the tumor microenvironment (TME). However, the complex interplay between immune cell infiltrates within the hypoxic TME of HCC remains to be elucidated. APPROACH AND RESULTS: We analyzed the immune landscapes of hypoxia-low and hypoxia-high tumor regions using cytometry by time of light, immunohistochemistry, and transcriptomic analyses. The mechanisms of immunosuppression in immune subsets of interest were further explored using in vitro hypoxia assays. Regulatory T cells (Tregs) and a number of immunosuppressive myeloid subsets, including M2 macrophages and human leukocyte antigen-DR isotype (HLA-DRlo ) type 2 conventional dendritic cell (cDC2), were found to be significantly enriched in hypoxia-high tumor regions. On the other hand, the abundance of active granzyme Bhi PD-1lo CD8+ T cells in hypoxia-low tumor regions implied a relatively active immune landscape compared with hypoxia-high regions. The up-regulation of cancer-associated genes in the tumor tissues and immunosuppressive genes in the tumor-infiltrating leukocytes supported a highly pro-tumorigenic network in hypoxic HCC. Chemokine genes such as CCL20 (C-C motif chemokine ligand 20) and CXCL5 (C-X-C motif chemokine ligand 5) were associated with recruitment of both Tregs and HLA-DRlo cDC2 to hypoxia-high microenvironments. The interaction between Tregs and cDC2 under a hypoxic TME resulted in a loss of antigen-presenting HLA-DR on cDC2. CONCLUSIONS: We uncovered the unique immunosuppressive landscapes and identified key immune subsets enriched in hypoxic HCC. In particular, we identified a potential Treg-mediated immunosuppression through interaction with a cDC2 subset in HCC that could be exploited for immunotherapies.
BACKGROUND AND AIMS: Hypoxia is one of the central players in shaping the immune context of the tumor microenvironment (TME). However, the complex interplay between immune cell infiltrates within the hypoxic TME of HCC remains to be elucidated. APPROACH AND RESULTS: We analyzed the immune landscapes of hypoxia-low and hypoxia-high tumor regions using cytometry by time of light, immunohistochemistry, and transcriptomic analyses. The mechanisms of immunosuppression in immune subsets of interest were further explored using in vitro hypoxia assays. Regulatory T cells (Tregs) and a number of immunosuppressive myeloid subsets, including M2 macrophages and human leukocyte antigen-DR isotype (HLA-DRlo ) type 2 conventional dendritic cell (cDC2), were found to be significantly enriched in hypoxia-high tumor regions. On the other hand, the abundance of active granzyme Bhi PD-1lo CD8+ T cells in hypoxia-low tumor regions implied a relatively active immune landscape compared with hypoxia-high regions. The up-regulation of cancer-associated genes in the tumor tissues and immunosuppressive genes in the tumor-infiltrating leukocytes supported a highly pro-tumorigenic network in hypoxic HCC. Chemokine genes such as CCL20 (C-C motif chemokine ligand 20) and CXCL5 (C-X-C motif chemokine ligand 5) were associated with recruitment of both Tregs and HLA-DRlo cDC2 to hypoxia-high microenvironments. The interaction between Tregs and cDC2 under a hypoxic TME resulted in a loss of antigen-presenting HLA-DR on cDC2. CONCLUSIONS: We uncovered the unique immunosuppressive landscapes and identified key immune subsets enriched in hypoxic HCC. In particular, we identified a potential Treg-mediated immunosuppression through interaction with a cDC2 subset in HCC that could be exploited for immunotherapies.