Macrophages treated with sEVs derived from plasma of HNSCC patients modulate immunosuppression

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 Theodoraki^1,5

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