|Beitragstitel||The influence of Head and Neck Squamous Cell Carcinoma (HNSCC) derived tumor exosomes (TEX) on immune cells in the tumor microenvironment.|
Increasingly immunotherapies are implemented into the clinical routine, thus it is of outmost importance to better understand the interaction of TEX and the immune system.TEX were shown to change t cells into an immunosuppressive phenotype and are therefore in direct competition with immune therapies. Our goal is to learn more about the effect of TEX on b cells, which are known to be increased in HNSCC patients.
Material and methods
Tumor biopsies were dissociated and analyzed after staining for CD39, CD24, CD38, CD20 with flow cytometry. Isolation of TEX was performed as described earlier with a combination of differential centrifugation and size-exclusion chromatography from PCI-13 cells lines. ATP (Sigma) was added as described. B cells were activated by CD40L and IL-4. CFSE-assay and dot blots was performed according to the manufacturer’s guidelines.
Ethic consent (EKNZ), Statistical analyses (Prism software).
We showed that immunosuppressive b cells (Bregs) are present in the tumor microenvironment. TEX and activation increase CD39 expression in b cells.
In the presence of 20 μM ATP, converted to adenosine, CD39 expression in b cells is decreased, while in higher ATP doses CD39 inhibition is reversed by TEX.
Analyzing multiple apoptotic factors in b cells revealed that significant changes occur in several proteins. Addition of TEX in lower doses of ATP to activated b cells showed a separate clustering as seen on heat map analyses.
Our experiments show that especially under the condition of ATP presence as usually seen in the tumor microenvironment, TEX exert effects on b cells that may favor immunosuppression and thus help in tumor immune escape.