Effect of plasma-derived Exosomes from head and neck cancer patients on primary Macrophages

Introduction As one of the most immunosuppressive cancers, head and neck squamous cell carcinomas (HNSCC) show an increased NF-κB activation with downstream production of Treg attracting immunosuppressive factors. Plasma-derived exosomes from HNSCC patients contain immune modulatory molecules, which contribute to the immunosuppressive tumor microenvironment (TME). Here, we investigate the influence of exosomes on NF-κB signaling and changes in immunosuppressive properties of macrophages.

Material & Methods Exosomes were isolated from plasma of HNSCC patients and healthy donors by size-exclusion chromatography. Primary monocytes were used to generate macrophages, which were incubated with exosomes to investigate their effects. NF-κB nuclear translocation and exosome internalization was determined and downstream signaling was evaluated by CCL5, CXCL12 and CCL22 ELISA. T cell attraction was investigated by migration assays. Polarization of macrophages was evaluated by measuring M1/M2 specific markers via Flow Cytometry.

Results Exosomes increased NF-κB activation in macrophages, which was reversible by NF-κB inhibitors. When adding exosomes from HNSCC patients during the differentiation process of monocytes to macrophages, we observed a shift to M2 macrophages. However, when adding exosomes after differentiation to M0 macrophages no big differences were seen. Differences in exosome internalization between M0, M1 and M2 macrophages were observed.

Discussion Plasma-derived exosomes from HNSCC patients alter immunosuppressive properties of macrophages and can influence the differentiation towards a M2 phenotype. The reversion of NF-κB activation by several inhibitors may be useful for future clinical therapeutic strategies on modulation of macrophages in the TME.

Funding information Deutsche Krebshilfe

Publication History

Article published online:
19 April 2024