Digital Commons Network^™

Functional Characterization Of Cancer-Associated Dna Polymerase Ε Variants, Stephanie R. Barbari

Theses & Dissertations

Replicative DNA polymerases ε (Polε) and δ (Polδ) achieve high fidelity DNA synthesis through a precise balance of polymerization and exonucleolytic proofreading. Errors that escape proofreading are corrected by DNA mismatch repair (MMR). Ultramutated human cancers with proficient MMR carry alterations in the exonuclease domain of Polε, which were initially predicted to abolish proofreading. However, functional studies in yeast of the most recurrent Polε-P286R variant suggested defects beyond a loss of exonuclease activity. Indeed, biochemical analysis of the yeast Polε-P286R analog revealed increased polymerization capacity in addition to decreased proofreading, which enables efficient mismatch extension and bypass of replication-blocking non-B …

Dna Polymerase Ε: Replication Error Prevention And Consequences Of A Cancer-Associated Mutation, Chelsea R. Bulock

Theses & Dissertations

Genome integrity is necessary to prevent mutations and disease. During eukaryotic DNA replication, DNA polymerases ε (Polε) and δ (Polδ) synthesize the leading and lagging strand, respectively. Polε and Polδ also have exonuclease activity that acts in series with post-replicative mismatch repair (MMR) to remove replication errors. Defects in proofreading and MMR lead to an increase in mutations and cause cancer in humans. This dissertation focuses on several unresolved issues involving the relationship between Polε and Polδ in replication error avoidance. First, despite an abundance of data supporting the one-strand-one-polymerase replication fork model, defects in the fidelity of Polε have …

Genomic And Transcriptomic Alterations In Metabolic Regulators And Implications For Anti-Tumoral Immune Response, Ryan J. King

Theses & Dissertations

Metabolic and immune alterations are ubiquitous hallmarks of cancer that are established during the foundational mutations and are further selected upon to generate highly aggressive tumors. Recent evidence suggests that cancer cells employ an altered metabolism to induce immune evasion. To further discover the relationship between metabolism and immunity in cancer, this thesis aimed to discover potential candidates of interest by first examining the mucin family for differences, as they exert a wide range of activities in cancer, including altered metabolism and immune alterations. Unique differences lead to further profiling in pancreatic and esophageal cancer. In pancreatic cancer, CD73 was …

From Development To Therapy: A Panoramic Approach To Further Our Understanding Of Cancer, Brittany Poelaert

Theses & Dissertations

Solid tumors, such as pancreatic cancer, often result in dismally low survival outcomes for patients due to insufficient understanding of disease development and progression. Pancreatic cancer is the fourth leading cause of cancer-related deaths in the United States and although oncogenic drivers (such as KRAS mutation or loss of tumor suppressor p53) and stages of disease development have been studied, further understanding of pancreatic cancer development is greatly needed. Studies from our laboratory have identified novel and varied functions of amyloid precursor-like protein 2 (APLP2) in the development and progression of pancreatic cancer. These functions include promoting cancer cell migration, …

The Role Of The Cxcr3 Signaling Axes In Pancreatic Ductal Adenocarcinoma, Andrew C. Cannon

Theses & Dissertations

Numerous cytokines promote pancreatic ductal adenocarcinoma (PDAC) progression and suppress anti-tumor immune response leading to poor prognosis in PDAC patients. Despite this, many cytokines, have not been investigated in PDAC. Bioinformatic analyses of PDAC microarray and RNA-Seq datasets were used to identify cytokines overexpressed in PDAC, confirm the expression of cognate receptors, determine the association of cytokines with patient survival and define key underlying molecular associations. Bioinformatic findings were validated using immunohistochemical (IHC) staining, comparative cytokine qPCR-array in Kras^LSL-G12D:TP53^LSL-R172H:Pdx1-Cre (KPC) and Kras^LSL-G12D:Pdx1-Cre (KC) PDAC models and multicolor immunofluorescence staining. Tail-vein injections of PDAC cells …

Molecular Mechanisms Governing Muscle Wasting In Cancer, Aneesha Dasgupta

Theses & Dissertations

Pancreatic cancer is the third-leading cause of cancer-related deaths in the United States. About 80 percent of the pancreatic cancer patients suffer from cachexia and, about one-third die due to complexities related to the syndrome. Cachexia leads to a loss in body weight and cachectic patients are refractory to chemotherapy. Despite recent advances, the mechanisms of pancreatic cancer- cachexia and the potential therapeutic interventions remain poorly evaluated.

Sirtuins represent a class of proteins that are regulated by metabolic fluctuations in tissues. We observed a reduced expression of Sirt1 in spontaneous PDAC mice muscles, human pancreatic cancer muscles, and myotubes treated …

The Role Of Zyxin And Limd1 In Mitosis And Cancer, Jiuli Zhou

Theses & Dissertations

The Hippo signaling pathway, originally discovered in Drosophila, consists of a core kinase cascade and has been subsequently demonstrated to control tissue growth and tumorigenesis. The core of this pathway contains MST1/2 (Mammalian sterile 20-like kinase 1/2), LATS1/2 (large tumor suppressor 1/2) and downstream effector named Yes-associated protein (YAP) and PDZ-binding motif (TAZ). MST1/2 transduce their kinase activity mainly through directly phosphorylating LATS1/2. Once phosphorylated and activated, LATS1/2 subsequently phosphorylate and inhibit YAP/TAZ from translocating to nucleus, thereby suppressing the expression of downstream pro-growth and survival genes. While recent studies provide important insight into the tumor suppressor properties of …

Regulation Of Canonical And Non-Canonical Hippo Pathway Components In Mitosis And Cancer, Seth Stauffer

Theses & Dissertations

The Hippo pathway is conserved regulator of organ size through control of proliferation, apoptosis, and stem-cell self-renewal. In addition to this important function, many of the canonical signaling members have also been shown to be regulated during mitosis. Importantly, Hippo pathway components are frequently dysregulated in cancers and have attracted attention as possible targets for improved cancer therapeutics. Further exploration of Hippo-YAP (yes-associated protein) signaling has revealed new regulators and effectors outside the canonical signaling network and has revealed a larger non-canonical network of signaling proteins in which canonical Hippo pathway components crosstalk with important cellular homeostasis and apoptosis signaling …

Electrophysiological Biomarkers Of Chemotherapy-Related Cognitive Impairment In Hematological Malignancy Patients, David E. Anderson

Theses & Dissertations

Multiple cancer populations frequently report cognitive impairment following treatment with chemotherapy agents (“chemo-brain”). Impaired neuropsychological performance is commonly reported in cognitive domains of attention and executive function. Understanding neural mechanisms underlying cognitive impairments is essential to developing prevention and rehabilitation strategies. Brain imaging studies frequently show chemotherapy-related impairments within the attentional control network, which is comprised of a constellation of cortical regions that govern reportedly impaired cognitive functions. In the current dissertation research, I developed a novel electrophysiology battery aimed at recording near-instantaneous neural activity within the attentional control network during cognitive task performance. Cancer patients diagnosed with hematological malignancy …

Development Of Neurotensin-Based Radiopharmaceuticals For Neurotensin-Receptor-1-Positive Tumors Targeting, Yinnong Jia

Theses & Dissertations

The neurotensin receptor 1 (NTR1) is overexpressed in many cancers, due to its role as a growth pathway. These NTR1-positive cancers include pancreatic, colon, prostate and breast cancers. In the radiopharmaceutical field, the overexpression of NTR1 in cancer has prompted the development of NTR1-targeted diagnostics and therapeutics. The neurotensin (NT) peptide exhibits low nanomolar affinity for NTR1 and has been the paradigm for NTR1-targeted agents. Since the 1980’s, radiolabeled NT analogs have been developed and evaluated for targeting NTR1-positive cancers. Since native NT is rapidly degraded in vivo by a variety of peptidases, a tremendous amount of effort has been …

Role Of Ecdysoneless In Erbb2/Her2 Mediated Breast Oncogenesis, Shalis A. Ammons

Theses & Dissertations

Breast cancer is the second leading cause of cancer related deaths in women in the United States. The human Epidermal Growth Factor 2 (ErbB2) gene amplification and/or receptor overexpression subtype of breast cancer accounts for 25% of all breast cancers. A crucial regulator of the ErbB2 signaling pathway is the heat shock protein 90 (Hsp90) and its interacting protein complex. One such complex is the R2TP/Prefoldin-like complex that is composed of four proteins, RUVBL1, RUVBL2, PIH1D1, and RPAP3 and seven prefoldin-like proteins. This complex has been shown to be involved in telomere elongation, ribosome biogenesis, protein stability; etc. We and …

Epacs: Epigenetic Regulators That Affect Cell Survival In Cancer., Catherine Murari

Theses & Dissertations

Cyclic adenosine monophosphate (cAMP) is a second messenger responsive to many external stimuli, playing an important role in cellular gene expression, metabolism, migration, differentiation, hypertrophy, apoptosis and secretion. All of these cellular functions are important in many diseases including cancer. Most of its effects were initially attributed to the classical protein kinase A (PKA) protein, but cellular functions such as proliferation and migration were found to be PKA independent and dependent on the newly discovered exchange proteins directly activated by cAMP (EPACs). EPACs are single polypeptides that primarily function as guanine exchange factors (GEFs) for Rap proteins that allow the …