Researcher(s)
- Marian Wehner, Biological Sciences, University of Delaware
- Matthew Shuhay, Biological Sciences, University of Delaware
Faculty Mentor(s)
- Deni Galileo, Department of Biological Sciences, University of Delaware
Abstract
One of the few known causes of glioblastoma (GBM) brain cancer is ionizing radiation. This is a concern because ionizing radiation is part of the standard treatment of GBM following removal of the tumor mass, along with chemotherapy. Radiation treatment potentially is further mutating the DNA of remaining GBM cells, leading to the selective survival of glioblastoma stem cells (GSCs) or creation of new GSCs from “differentiated” GBM cells. GSCs are thought to be the main cause of tumor growth and recurrence, and they are resistant to both chemotherapy and radiation treatment. To test the hypothesis that radiation increases “stemness” in GBM cells, two patient-derived GSC lines isolated in our lab were irradiated with 8 Gy of radiation each: GSC 2016-4 and GSC 2015-2. These irradiated cells were then grown in stem cell media with growth factors, and also in differentiation media to determine if they became resistant to being differentiated. Multiple experiments are being conducted to compare marker expression and behavior of the different cells. Cell immunostaining is being performed for stem cell “markers,” such as nestin, sox-2, integrin α6, and L1CAM. Flow cytometry analysis is then used on the immunostained cells in order to determine the percentage of each cell type expressing the markers. We found that sox-2 expression decreased in some irradiated GSCs. In vitro SuperScratch assays and cell cycle analyses are also being done in order to determine motility and proliferation rates of irradiated stem cells, respectively. Fluorescently labeled cells also were injected in chicken embryos to determine their ability to form tumors in vivo and invade surrounding brain tissue. In some tumors formed by irradiated and non-irradiated GSCs, the cells “sorted out” whereby the irradiated GSCs were preferentially located in the interior of the tumor.