Showcase of Undergraduate Research and Creative Endeavors (SOURCE)

The Effects of RYBP on Apoptosis in Glioblastoma Cells

Glioblastoma is a deadly, fast growing, and aggressive type of brain cancer that has poor prognosis and limited treatment options. We investigated the phenotypic effects of the tumor suppressor gene RING1- and YY1-binding protein (RYBP) on apoptosis, a form of programmed cell death, in glioblastoma cell lines. We hypothesized that forced RYBP expression would activate caspases, leading to increased apoptosis. Using a GFP-expressing plasmid, we optimized transient transfection conditions in U118 glioblastoma cells to determine ideal transfection conditions needed to express RYBP. We found that 1 µg of plasmid DNA and 7.5 µL of Lipofectamine 3000 led to the highest transfection rate. However, when we transfected U118 cells with either a vector control or RYBP-expressing plasmid, RYBP expression could not be detected, suggesting the transfection did not work. Therefore, we altered our approach and used U118 and T98 glioblastoma cell lines already stably transduced with control or RYBP-expressing lentivirus. A Western Blot verified ectopic RYBP expression in both the U118 and T98 infected cell lines compared to cells transduced with a control lentivirus. Moreover, forced RYBP expression in T98 cells reduced full-length caspase-3 and increased cleaved caspase-3 levels, suggesting that RYBP activates apoptotic responses in T98 cells. Further research will examine whether RYBP may sensitize glioblastoma cells to apoptosis that is induced by DNA damaging agents, such as the chemotherapy Temozolomide. Further, the mechanism by which RYBP facilitates apoptosis in glioblastoma is also worth further study.