EXPLORING THE EFFECT OF EXOSOMES AND RADIATION ON GLIOBLASTOMA CANCER CELLS Open Access

Glioblastoma is the most common and aggressive type of brain cancer, with higher incidences in aging adults over 75 and little to no long-term survival or cure. The median survival time under the current standard of care, surgical resection and chemoradiation, is 15-18 months. Glioblastoma tumors consist of multiple cell types, including mature brain cells in cell cycle arrest and cancer stem cells (CSCs) that replenish cancer cell populations. However, the cancerous non-stem cells are induced into a cell fate called glioma-initiating cells in response to radiation, where they begin to express stem-like phenotypes. Glioma-initiating cells proliferate at an aggressive rate and are the reason for cancer recurrence, making them a necessary target for new and more effective therapeutics. This research is studying the effect of exposure to exosomes, extracellular vesicles that carry proteins and RNA, on the stem-like phenotype expression of irradiated non-stem cells. Irradiated glioblastoma cells were exposed to varying concentrations of exosomes isolated from glioblastoma CSCs in vitro. The results showed a decrease in ZsGreen expression, a marker for stem-like phenotypes, as exosome concentration increased. Exposure of glioblastoma cancer cells to exosomes post-irradiation decreased the rate of transition to glioma-initiating cells. This suggests that CSC exosomes may signal that stem cells are present, decreasing the need for the formation of glioma-initiating cells. Further research is necessary to better understand the role of exosomes in glioblastoma tumors, however, this result may suggest exosomes as a potential way to delay or reduce the aggressive nature of glioblastoma cancer recurrence.