Head and neck squamous cell carcinoma-derived small extracellular vesicles mediate Ca²⁺-dependent platelet activation and aggregation through tissue factor

ABSTRACT: Head and neck squamous cell carcinoma (HNSCC) is an aggressive malignancy, characterized by poor clinical outcomes, primarily driven by high rate of locoregional recurrence and metastasis. Extensive heterogeneity among the tumor cells as well as modulation of a highly immunosuppressive tumor microenvironment shape cancer progression. Shedding of small extracellular vesicles (sEVs) derived from tumor cells is a critical mediator of the disease initiating horizontal transfer of tumor components into platelets. HNSCC-derived sEVs isolated from HNSCC cell lines (SAS, UD-SCC 5) using Size exclusion chromatography and characterized via Flow cytometry, Electron microscopy, Nanoparticle tracking analysis and Western blotting, were used to induce platelet activation and aggregation, measured by aggregometry, flow cytometry, as well as the release of chemokines and ATP, which were quantified using Enzyme-linked immunosorbent assays (ELISA). Mechanistic investigations included inhibitor assays, thrombin activity measurements, and proteomic analyses. Unexpectedly we can show that sEVs do not activate PLTs through the FcγRIIa–IgG axis but platelet activation and aggregation is induced in a calcium-dependent manner, primarily mediated by sEV-associated Tissue factor. Proteomic analysis confirmed the presence of Tissue factor in these vesicles, implicating its involvement in initiating the coagulation cascade, that leads to platelet activation and aggregation.

INSTRUMENT(S): Orbitrap Eclipse

ORGANISM(S): Homo Sapiens (human)

DISEASE(S): Tongue Squamous Cell Carcinoma,Oral Cavity

SUBMITTER: Julia Mergner  

LAB HEAD: Julia Mergner

PROVIDER: PXD060122 | Pride | 2025-05-07

REPOSITORIES: Pride