Background
As one of the most immunosuppressive cancers, patients with head and neck squamous cell carcinomas (HNSCC) typically show early formation of metastasis and poor treatment response. Plasma-derived small EVs (sEVs) from HNSCC patients contain molecules, which can contribute to the immunosuppressive profile of patients. Here, we investigate the influence of HNSCC plasma-derived sEVs on macrophage function and the contribution of sEV-primed macrophages to immune modulation.
Methods
sEVs were isolated from plasma of HNSCC patients and healthy donors by size-exclusion chromatography (EV-Track: EV200068). Monocytes were used to generate primary macrophage cultures, which were incubated with plasma-derived sEVs to investigate their effects on the transcriptome, analyzed by RNA-Seq and the proteome by mass spectrometry, flow cytometry and cytokine multiplex assay. To examine immune modulatory functions of sEV-primed macrophages, migration and activation of regulatory and CD8(+) T cells were examined.
Results
Incubation with sEVs changed the proteome of macrophages in a time-dependent manner, supposedly by modulating processes rather than by transferring proteins from sEVs. sEVs do not polarize macrophages clearly to M1 or M2 phenotype, but show a mixed, however pro-inflammatory phenotype. CD8(+) T cells are attracted by sEVs but get inactivated when incubated with sEVs, while they are less attracted to sEV-treated macrophages. Regulatory T cells, however, are attracted by sEVs as well as sEV-treated macrophages.
Conclusion
Plasma-EV-treated macrophages contribute to modulation of the immunosuppressive TME as well as the pre-metastatic niche, i.e. by modulating T cell migration. Since macrophages are major drivers of tumor progression, metastasis and therapy resistance, future therapeutic strategies on modulation of tumor-associated macrophages through targeting sEVs may be useful.
Keywords
HNSCC, Blood-EVs, macrophages, T cell migration, TME
Funding/Acknowledgments
Deutsche Krebshilfe
Authors
Diana Huber1, Tsima Abou Kors1, Linda Hofmann1, Monika Pietrowska2, Marta Gawin2, Ramin Lotfi 3,4, Thomas K Hoffmann1, Cornelia Brunner1, Marie-Nicole Theodoraki1,5
1 Department of Otorhinolaryngology, Head and Neck Surgery, Ulm University Medical Center, Ulm, Germany
2 Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Gliwice Branch, Gliwice, Poland
3 Institute of Clinical Transfusion Medicine and Immunogenetics, German Red Cross Blood Transfusion Service Baden Wuerttemberg- Hessia, Ulm, Germany
4 Institute for Transfusion Medicine, University Hospital Ulm, Germany
5 Department of Otorhinolaryngology, Head and Neck Surgery, Klinikum rechts der Isar, Technical University Munich, Munich, Germany
