Tumor-derived extracellular vesicles: insights into bystander effects of exosomes after irradiation

This review article aims to address the kinetic of TDEs in cancer cells pre- and post-radiotherapy. Radiotherapy is traditionally
used for the treatment of multiple cancer types; however, there is growing evidence to show that radiotherapy exerts NTEs on
cells near to the irradiated cells. In tumor mass, irradiated cells can affect non-irradiated cells in different ways. Of note, exosomes
are nano-scaled cell particles releasing from tumor cells and play key roles in survival, metastasis, and immunosuppression of
tumor cells. Recent evidence indicated that irradiation has the potential to affect the dynamic of different signaling pathways such
as exosome biogenesis. Indeed, exosomes act as intercellular mediators in various cell communication through transmitting bio-
molecules. Due to their critical roles in cancer biology, exosomes are at the center of attention. TDEs contain an exclusive
molecular signature that they may serve as tumor biomarker in the diagnosis of different cancers. Interestingly, radiotherapy and
IR could also contribute to altering the dynamic of exosome secretion. Most probably, the content of exosomes in irradiated cells
is different compared to exosomes originated from the non-irradiated BCs. Irradiated cells release exosomes with exclusive
content that mediate NTEs in BCs. Considering variation in cell type, IR doses, and radio-resistance or radio-sensitivity of
different cancers, there is, however, contradictions in the feature and activity of irradiated exosomes on neighboring cells.