Effect of plasma-derived exosomes from HNSCC patients on NF-κB signaling in 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 factors. Plasma-derived exosomes from HNSCC patients contain molecules, which can contribute to the immunosuppressive tumor microenvironment (TME). Here, we investigate the influence of plasma-derived exosomes of HNSCC patients on macrophages.

Material & Methods Exosomes were isolated from plasma of HNSCC patients and healthy donors by size-exclusion chromatography. Monocytes from buffy coats were used to generate primary macrophage cultures, which were incubated with plasma-derived exosomes to investigate their effects. NF-κB nuclear translocation was determined and downstream signaling was evaluated by CCL5, CXCL10 and CCL22 ELISA. Polarization of macrophages was determined by measuring M1/M2 specific markers via Flow Cytometry.

Results Exosomes increased NF-κB activation in macrophages, which was reversible by addition of NF-κB inhibitors Bay, CAPE and curcumin. Interestingly, activated NF-κB signaling resulted in production of higher levels of CCL22 induced by exosomes from HPV positive, but not HPV negative patients. Regarding macrophage polarization, exosomes did not induce M1 type macrophages. Exosomes from healthy donors, but not HNSCC patients prevented M2 polarization.

Discussion Plasma-derived exosomes from HNSCC patients can alter immunosuppressive properties of macrophages. The reversion of NF-κB activation by several inhibitors may be useful for future clinical therapeutic strategies on modulation of tumor-associated macrophages through targeting exosomes in the TME. However, HPV-status of the patients has to be considered.

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Artikel online veröffentlicht:
12. Mai 2023