Yasui, Linda S.
M.S. (Master of Science)
Department of Biological Sciences
Glioblastoma (GBM) is a highly aggressive cancer that forms from the astrocytes of the brain. Poor prognosis and rather unsuccessful treatment regimens have left researchers and patients looking for new therapeutic strategies to combat this dreadful disease. Following tumor resection and radiotherapy combined with temozolomide, survival only remains around 15 months. Recurrence is very commonly seen, and urgently needs to be further understood. Autophagy is an important mechanism within cancer cells, which allows for cellular organelle/amino acid recycling and thus contributes to energy metabolism. Autophagy machinery has been shown to control cell death within cancer cells, leading to our interest in radiation's affect on autophagy and its completion. To analyze this affect, we set up several methods to help quantify autophagic flux in GBM cells on days 0, 3, 5, or 7 after exposure to 0 and 2 Gy gamma radiation. By using autophagic flux reporters such as p62, we were able to detect flux via protein content over time as well as visualization and quantification of autophagy changes over time using LC3-eGFP-mCherry transfected cells. Preliminary results show cells adapt to both nutrient and radiation stress by maintaining p62 levels, an early stress response gene. Clearly, irradiation induces autophagic flux in both U87 and U251 cell lines, though in differing fashions. This induction of autophagy differs however between the cell lines, with U87 seeing changes on day three following irradiation, while U251 cells see changes on day five. These results argue that the increase in sensitivity to radiation seen in U251 cells could be attributed to a blockage of completion of autophagy seen in the later days of our experiment, arguing blockage of autophagy could correlate with an decrease in cell survival following irradiation.
Ozgen, Devron, "Modulation of autophagy in GBM cells by clinical doses of gamma radiation" (2018). Graduate Research Theses & Dissertations. 4009.
Northern Illinois University
Rights Statement 2