The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences Dissertations and Theses (Open Access)
Author ORCID Identifier
Date of Graduation
Doctor of Philosophy (PhD)
Raghu Kalluri MD., PhD.
Menashe Bar-Eli, PhD.
Joya Chandra, PhD.
Frederick Lang, MD.
Katharina Schlacher, PhD.
Exosomes are heterogeneous nanoparticles 50-150nm in diameter. Exosomes contain many functional cargo components, such as protein, DNA, and RNA. While protein and RNA exosome content has been extensively studied, very little work has been done to characterize exosomal DNA. Here, we demonstrate that exosomal DNA is heterogeneous and its packaging into exosomes is dependent on the cell of origin. Furthermore, through a rigorous assessment of various isolation methods, we identify Size Exclusion Chromatography (SEC) as the best method for the isolation of exosomal DNA for downstream applications. Additionally, we evaluate the methylation status of exosomal DNA and demonstrate that exosomal DNA is both methylated and fully recapitulates the methylation patterns observed in the cells of origin. We also propose a potential mechanism for DNA packaging into exosomes by disruption of the nuclear membrane. Finally, we investigated the ability of exosomes to induce paracrine DNA damage responses (DDR) in treatment-naïve cells. We explore the specificity of exosome-induced DDR to exosomes released by damaged cancer cells, and provide a potential molecular mechanism of action via the shuttling of activated DDR pathway proteins.
Exosomes, DNA, Methylation, DNA Damage Response, Liquid Biopsy
Biological Phenomena, Cell Phenomena, and Immunity Commons, Diagnosis Commons, Medical Cell Biology Commons, Medical Genetics Commons, Medical Molecular Biology Commons, Nanomedicine Commons, Oncology Commons, Therapeutics Commons