Tasmanian devil facial tumour-derived extracellular vesicles reveal mesenchymal transition markers and adhesion molecules related to metastasis.

Tasmanian devils are threatened with extinction by Devil Facial Tumor Disease (DFTD), which consists of two genetically independent transmissible cancers (DFT1 and DFT2). Both cancers typically cause death due to metastases. However, the mechanisms underpinning DFTD metastasis are not well understood. The nano-sized, membrane-enclosed extracellular vesicles (EVs) released by cancer cells have been implicated in metastasis, thus EVs may yield insights into DFTD metastasis. Here, we characterized EVs derived from cultured DFT1, DFT2, and devil fibroblast cells. The proteome of EVs was determined using data independent acquisition mass spectrometry and an in-house spectral library of >1,500 proteins. Relative to EVs from fibroblast cells, EVs from both DFT1 and DFT2 cell lines expressed higher levels of proteins associated with cell adhesion and focal adhesion functions. Furthermore, hallmark proteins of epithelial mesenchymal transition, which are associated with increased metastatic features in some cancers, were enriched in DFT2 EVs relative to DFT1 EVs, suggesting differential aggressiveness between the cancers and a target for novel differential diagnosis biomarkers. This first EV-based investigation of DFTD increases our understanding of the cancers EVs and their possible involvement in the metastatic process. As EVs are found in body fluids, these results offer potential for non-invasive biomarkers for DFTD.