Publication Date

2019

Document Type

Dissertation/Thesis

First Advisor

Yasui, Linda

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Biological Sciences

Abstract

GBM is the most common CNS derived malignancy diagnosed each year. The median survival time to date is between 14.6 to 16.7 months for patients suffering from the disease. Clinical trials and research has yet to yield a breakthrough treatment. The invasive nature of GBM to surrounding tissue typically poses a challenge for complete surgical resection of the tumor, and radiotherapy remains a predominant treatment modality. The NHEJ pathway is main repair pathway responsible for repairing lethal radiation damage. As a result, this study used the CRISPR-Cas9 system to genetically engineer two GBM cell lines lacking expression of an essential kinase in the NHEJ pathway known as, DNA-PKcs. Cells lacking DNA-PKcs expression were significantly sensitized to ionizing radiation. Also, histone variant H2AX phosphorylated at Serine-139, also referred to as γH2AX, was used as a biomarker for DSBs throughout the study. Levels of γH2AX were monitored over a 72-hour period following 2Gy of ionizing radiation exposure during this study. Cells lacking DNA-PKcs expression but expressing wild-type p53 had delayed repair kinetics. However, cells lacking DNA-PKcs expression and expressing mutated p53 had an observed increase in levels of γH2AX over the 72-hour period following irradiation. The accumulation of γH2AX observed is attributed to improper cell cycle arrest and increased genomic instability in the absence of DNA-PKcs.

Extent

114 pages

Language

eng

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

Media Type

Text

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