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Stary V, Wolf B, Unterleuthner D, List J, Talic M, Laengle J, Beer A, Strobl J, Stary G, Dolznig H, Bergmann M. Short-course radiotherapy promotes pro-inflammatory macrophages via extracellular vesicles in human rectal cancer. J Immunother Cancer 2021; 8:jitc-2020-000667. [PMID: 32817359 PMCID: PMC7437887 DOI: 10.1136/jitc-2020-000667] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/02/2020] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Tumor-associated macrophages (TAM) constitute the most abundant immune cells in the tumor stroma initiating pro-inflammatory (M1) or immunosuppressive (M2) responses depending on their polarization status. Advances in tumor immunotherapy call for a detailed understanding of potential immunogenic mechanisms of irradiation routinely applied in rectal cancer patients. METHODS To test the effects of radiotherapy on TAM, we ex vivo irradiated tissue samples of human rectal cancer and assessed the phenotype by flow cytometry. We furthermore evaluated the distribution of leucocyte subsets in tissue sections of patients after short-course radiotherapy and compared findings to non-pretreated rectal cancer using an immunostaining approach. Organotypic assays (OTA) consisting of macrophages, cancer-associated fibroblast and cancer cell lines were used to dissect the immunological consequences of irradiation in macrophages. RESULTS We demonstrate that short-course neoadjuvant radiotherapy in rectal cancer patients is associated with a shift in the polarization of TAM towards an M1-like pro-inflammatory phenotype. In addition, ex vivo irradiation caused an increase in the phagocytic activity and enhanced expression of markers associated with stimulatory signals necessary for T-cell activation. In OTA we observed that this alteration in macrophage polarization could be mediated by extracellular vesicles (EV) derived from irradiated tumor cells. We identified high mobility group box 1 in EV from irradiated tumor cells as a potential effector signal in that crosstalk. CONCLUSIONS Our findings highlight macrophages as potential effector cells upon irradiation in rectal cancer by diminishing their immunosuppressive phenotype and activate pro-inflammation. Our data indicate that clinically applied short-term radiotherapy for rectal cancer may be exploited to stimulate immunogenic macrophages and suggest to target the polarization status of macrophages to enhance future immunotherapeutic strategies.
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Affiliation(s)
- Victoria Stary
- Division of General Surgery, Department of Surgery, Comprehensive Cancer Center, Medical University of Vienna, Vienna, Vienna, Austria
| | - Brigitte Wolf
- Division of General Surgery, Department of Surgery, Comprehensive Cancer Center, Medical University of Vienna, Vienna, Vienna, Austria
| | - Daniela Unterleuthner
- Institute of Medical Genetics, Medical University of Vienna, Vienna, Vienna, Austria
| | - Julia List
- Division of General Surgery, Department of Surgery, Comprehensive Cancer Center, Medical University of Vienna, Vienna, Vienna, Austria
| | - Merjem Talic
- Division of General Surgery, Department of Surgery, Comprehensive Cancer Center, Medical University of Vienna, Vienna, Vienna, Austria
| | - Johannes Laengle
- Division of General Surgery, Department of Surgery, Comprehensive Cancer Center, Medical University of Vienna, Vienna, Vienna, Austria
| | - Andrea Beer
- Department of Pathology, Medical University of Vienna, Vienna, Vienna, Austria
| | - Johanna Strobl
- Department of Dermatology, Medical University of Vienna, Vienna, Vienna, Austria
| | - Georg Stary
- Department of Dermatology, Medical University of Vienna, Vienna, Vienna, Austria
| | - Helmut Dolznig
- Institute of Medical Genetics, Medical University of Vienna, Vienna, Vienna, Austria
| | - Michael Bergmann
- Department of Visceral Surgery, Comprehensive Cancer Center, Medical University of Vienna, Vienna, Vienna, Austria
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Stary V, Unterleuthner D, Wolf B, Talic M, Strobl J, Beer A, Dolznig H, Bergmann M. Irradiated cancer exosomes promote M1-like polarization of macrophages and enhance their anti-tumoral responses. Eur J Cancer 2019. [DOI: 10.1016/j.ejca.2019.01.097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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