Extracellular vesicle mediated signalling in oral cancer progression

Objectives: Oral cancer includes cancers of the throat, tongue and mouth with 6767 new cases and 2119 deaths per year; worryingly mortality rates are slowly on the rise. Efforts to improve survival are hampered by a limited understanding of the underlying molecular complexity of the disease. The objectives of this study are to identify the role extracellular vesicle (EVs) mediated signalling plays in oral cancer development. EVs are nanometre sized vesicles with a range of bioactive contents released by cells, but released in higher numbers by cancer cells. Since the early 2000’s these vesicles have been thought of as a new signalling system with a vital role in driving cancer progression. Developing tumours exist as a complex milieu comprising multiple cell types, which require complex cross talk as the tumour develops. Using fluorescent staining techniques this study will identify potential vesicle mediated interactions between the different cell types of the oral cancer microenvironment.
Methods: EVs were extracted from the culture media of oral cancer cell lines using ultracentrifugation and then characterized using transmission electron microscopy, western blotting and tuneable resistive pulse sensing. EVs were labelled with fluorescent markers and transferred to cells of a different line to visualise transfer of RNA.
Results: We have successfully isolated and characterised EVs from a panel of cell lines representative of the stages of oral cancer development and confirmed their presence by western blot and transmission electron microscopy. Using fluorescently labelled EVs the horizontal transfer of RNA between oral cancer cells and stromal cells that would be present in the tumour microenvironment has been visualized.
Conclusions: Using a combination of techniques the beginnings of an EV mediated signalling network in the oral cancer microenvironment has been revealed. Future work will expand on this by focusing on the RNA and protein cargo of the isolated EVs in order to identify their roles in oral cancer progression.