The purpose of this thesis is to examine familial hypercholesterolemia (FH) and emerging pharmacogenomics therapies that propose to lower serum low density lipid (LDL) levels. The search of various data bases resulted in nine research articles being selected for review. Syntheses of the articles suggest emerging phamacogenomic drug therapy can improve treatment outcomes for individuals with a diagnosis of FH. The Human Genome Project (HGP) has had far reaching applications for genomic technologies and pharmacagenomic interventions, tailored to human conditions associated with select genomic traits. Synthesis of nine research articles demonstrate that little is known on the topic and reveals extensive gaps in the evidence. This thesis concludes with implications for nursing education, practice, policy and research along with limitations are noted.

Thesis (Ph. D.) -- University of Texas Southwestern Medical Center at Dallas, 2004. / Vita. Bibliography: 106-117.

First identified over a decade ago, Astrocyte Elevated Gene-1 (AEG-1) has been studied extensively due to early reports of its overexpression in various cancer cell lines. Research groups all over the globe including our own have since identified AEG-1 overexpression in cancers of diverse lineages including cancers of the liver, colon, skin, prostate, breast, lung, esophagus, neurons and neuronal glia as compared to matched normal tissue. A comprehensive and convincing body of data currently points to AEG-1 as an essential component, critical to the progression and perhaps onset of cancer. AEG-1 is a potent activator of multiple pro-tumorigenic signal transduction pathways such as mitogen-activated protein extracellular kinase (MEK)/ extracellular signal-regulated kinase (ERK), phosphotidyl-inositol-3-kinase (PI3K)/Akt/mTOR, NF-κB and Wnt/β-catenin pathway. In addition, studies show that AEG-1 not only alters global gene and protein expression profiles, it also modulates fundamental intracellular processes, such as transcription, translation and RNA interference in cancer cells most likely by functioning as a scaffold protein. The mechanisms by which AEG-1 is overexpressed in cancer have been studied extensively and it is clear that multiple layers of regulation including genomic amplification, transcriptional, posttranscriptional, and posttranslational controls are involved however; the mechanism by which AEG 1 itself induces its oncogenic effects is still poorly understood. Just as questions remain about the exact role of AEG-1 in carcinogenesis, very little is known about the role of AEG-1 in regulating normal physiological functions in the liver. With the help of the Massey Cancer Center Transgenic/Knockout Mouse Core, our lab has successfully created a germline-AEG-1 knockout mouse (AEG-1-/-) as a model to interrogate AEG-1 function in vivo. Here I present the insights gained from efforts to analyze this novel AEG-1-/- mouse model. Aspects of the physiological functions of AEG-1 will be covered in chapter two wherein details of the characterization of the AEG-1-/- mouse are described including the role of AEG-1 in lipid metabolism. Chapter three discusses novel discoveries about the specific role of AEG-1 in mediating hepatocarcinogenesis by modulating NF-κB, a critical inflammatory pathway. First identified over a decade ago, Astrocyte Elevated Gene-1 (AEG-1) has been studied extensively due to early reports of its overexpression in various cancer cell lines. Research groups all over the globe including our own have since identified AEG-1 overexpression in cancers of diverse lineages including cancers of the liver, colon, skin, prostate, breast, lung, esophagus, neurons and neuronal glia as compared to matched normal tissue. A comprehensive and convincing body of data currently points to AEG-1 as an essential component, critical to the progression and perhaps onset of cancer. AEG-1 is a potent activator of multiple pro-tumorigenic signal transduction pathways such as mitogen-activated protein extracellular kinase (MEK)/ extracellular signal-regulated kinase (ERK), phosphotidyl-inositol-3-kinase (PI3K)/Akt/mTOR, NF-κB and Wnt/β-catenin pathway. In addition, studies show that AEG-1 not only alters global gene and protein expression profiles, it also modulates fundamental intracellular processes, such as transcription, translation and RNA interference in cancer cells most likely by functioning as a scaffold protein. The mechanisms by which AEG-1 is overexpressed in cancer have been studied extensively and it is clear that multiple layers of regulation including genomic amplification, transcriptional, posttranscriptional, and posttranslational controls are involved however; the mechanism by which AEG 1 itself induces its oncogenic effects is still poorly understood. Just as questions remain about the exact role of AEG-1 in carcinogenesis, very little is known about the role of AEG-1 in regulating normal physiological functions in the liver. With the help of the Massey Cancer Center Transgenic/Knockout Mouse Core, our lab has successfully created a germline-AEG-1 knockout mouse (AEG-1-/-) as a model to interrogate AEG-1 function in vivo. Here I present the insights gained from efforts to analyze this novel AEG-1-/- mouse model. Aspects of the physiological functions of AEG-1 will be covered in chapter two wherein details of the characterization of the AEG-1-/- mouse are described including the role of AEG-1 in lipid metabolism. Chapter three discusses novel discoveries about the specific role of AEG-1 in mediating hepatocarcinogenesis by modulating NF-κB, a critical inflammatory pathway.

Huntington’s disease is an incurable, progressive neurological disorder characterized by loss of motor control, psychiatric dysfunction, and eventual dystonia leading to death. Despite the fact that this disorder is caused by a mutation in one single gene, there is no cure. The mutant Huntingtin (mHtt) protein is expressed ubiquitously throughout the brain but frank cell death is limited to the striatum. Recent work has suggested that Rhes, Ras homolog enriched in striatum, which is selectively expressed in the striatum, may play a role in Huntington’s disease neuropathology. In vitro studies have shown Rhes to be an E3 ligase for the post-translational modification protein SUMO. Rhes increases binding of SUMO to mHtt which competes for the same binding site as Ubiquitin. SUMOylation of mHtt leads to disaggregation and cellular death, whereas ubiquitination leads to aggregation and cellular protection. In a previous study we showed that deletion of Rhes caused a decrease in the Huntington’s disease phenotype in mice. We hypothesized that mice lacking Rhes would also show increased aggregation in the striatum and this increased aggregation would correlate in a rescue of behavioral symptoms. Despite the prior in vitro and in vivo evidence, deletion of Rhes in vivo did not alter the aggregation of mHtt in the striatum of mice however deletion of Rhes still showed a rescue from the diseased phenotype. This result would indicate that deletion of Rhes alters the neurobehavioral phenotype of Huntington’s disease through a different pathway than promoting aggregation in striatal cells.

The three dimensional structure of the human genome is known to play a critical role in gene function and expression. I used chromosome conformation capture (3C) and 3C-carbon copy (5C) techniques to investigate the three-dimensional structure of the cystic fibrosis transmembrane conductance regulator (CFTR) locus. This is an important disease gene that, when mutated, causes cystic fibrosis. 3C experiments identified four distinct looping elements that contact the CFTR gene promoter only in CFTR-expressing cells. Using 5C, I expanded the region of study to a 2.8 Mb region surrounding the CFTR gene. The 5C study shows 7 clear topologically associating domains (TADs) present at the locus, identical in all five cell lines tested, regardless of gene expression status. CFTR and all its known regulatory elements are contained within one TAD, suggesting TADs play a role in constraining promoters to a local search space. The four looping elements identified in the 3C experiment and confirmed in the 5C experiment were then tested for enhancer activity using a luciferase assay, which showed that elements III and IV could act as enhancers. These elements were tested against a library of human transcription factors in a yeast one-hybrid assay to identify potential binding proteins. Element III gave two strong candidates, TCF4 and LEF1. A literature search supported these transcription factors as playing a role in CFTR gene expression. Overall, this work represents a model locus that can be used to test important questions regarding the role of three dimensional looping on gene expression.

Glioblastoma multiforme (GBM) is the most common and aggressive primary brain tumor. The current standard-of-care treatment including surgery, radiation and temozolomide (TMZ) chemotherapy does not prolong the survival satisfactorily. Here we have tested the feasibility, efficacy and safety of a potential gene therapy approach using AAV as gene delivery vehicle for treatment of GBM. Interferon-beta (IFNβ) is a cytokine molecule also having pleiotropic anticancerous properties. Previously it has been shown by our group that AAV mediated local (intracranial) gene delivery of human IFNβ (hIFNβ) could be an effective treatment for non-invasive human glioblastoma (U87) in orthotopic xenograft mouse model.But as one of the major challenges to treat GBM effectively in clinics is its highly invasive property, in the current study we first sought to test the efficacy of our therapeutic model in a highly invasive human GBM (GBM8) xenograft mouse model. One major limitation of using the xenograft mouse model is that these mice are immune-compromised. Moreover, as IFNβ does not interact with cross-species receptors, the influence of immune systems on GBM remains largely untested. Therefore to test the therapeutic approach in an immune-competent mouse model, we next treated a syngeneic mouse GBM model (GL261) in an immune-competent mouse (C57B6) with the gene encoding the species-matched IFNβ (mIFNβ). We also tested if combination of this IFNβ gene therapy with the current standard chemotherapeutic drug (TMZ) is more effective than any one of the therapeutic modes alone. Finally, we tested the long term safety of the AAV-mIFNβ local gene therapy in healthy C57B6 mice. Next, we hypothesized that global genetic engineering of brain cells expressing secretory therapeutic protein like hIFNβ could be more beneficial for treatment of invasive, migratory and distal multifocal GBM. We tested this hypothesis using systemic delivery of AAV9 vectors encoding hIFNβ gene for treatment of GBM8 tumor in nude mice. Using in vivo bioluminescence imaging of tumor associated firefly luciferase activity, long term survival assay and histological analysis of the brains we have shown that local treatment of AAV-hIFNβ for highly invasive human GBM8 is therapeutically beneficial at an early growth phase of tumor. However, systemic delivery route treatment is far superior for treating multifocal distal GBM8 tumors. Nonetheless, for both delivery routes, treatment efficacy is significantly reduced when treated at a later growth phase of the tumor. In syngeneic GL261 tumor model study, we show that local AAV-mIFNβ gene therapy alone or in combination with TMZ treatment can provide significant survival benefit over control or only TMZ treatment, respectively. However, the animals eventually succumb to the tumor. Safety study in the healthy animals shows significant body weight loss in some treatment groups, whereas one group shows long term survival without any weight loss or any noticeable changes in the external appearances. However, histological analysis indicates marked demyelinating neurotoxic effects upon long term exposures to mIFNβ over-expressions in brain. Overall, we conclude from this study that AAV-IFNβ gene therapy has great therapeutic potential for GBM treatment in future, but the therapeutic window is small and long term continuous expression could have severe deleterious effects on health.

Genomic instability, in the form of gene mutations, insertions/deletions, and gene amplifications, is one of the hallmarks in many types of cancers and other inheritable genetic disorders. Trinucleotide repeat (TNR) disorders, such as Huntington’s disease (HD) and Myotonic dystrophy (DM) can be inherited and repeats may be extended through subsequent generations. However, it is not clear how the CAG repeats expand through generations in HD. Two possible repeat expansion mechanisms include: 1) polymerase mediated repeat extension; 2) persistent TNR hairpin structure formation persisting in the genome resulting in expansion after subsequent cell division. Recent in vitro studies suggested that a family A translesion polymerase, polymerase θ (Polθ), was able to synthesize DNA larger than the template DNA. Clinical and in vivo studies showed either overexpression or knock down of Polθ caused poor survival in breast cancer patients and genomic instability. However, the role of Polθ in TNR expansion remains unelucidated. Therefore, we hypothesize that Polθ can directly cause TNR expansion during DNA synthesis. The investigation of the functional properties of Polθ during DNA replication and TNR synthesis will provide insight for the mechanism of TNR expansion through generations.

Background: Disruptive technology describes technology that is significantly more advanced than previous iterations, such as: 3D printing, genetic manipulation, stem cell research, innovative surgical procedures, and computer-based charting software. These technologies often require extensive overhauls to implement into older systems and must overcome many difficult financial and societal complications before they can be widely used. In a field like healthcare that makes frequent advancements, these difficulties can mean that the technology will not be utilized to its full potential or implemented at all. Objective: To determine the inhibiting factors that prevent disruptive technology from being implemented in conventional healthcare. Methods: Peer reviewed articles were gathered from Cumulative Index to Nursing and Allied Health Literature (CINAHL), Educational Resources Information Center (ERIC), Elton B. Stephens Co. Host (Ebsco Host), Medical Literature On-line (Medline), and Psychological Information Database (PsychINFO). Articles were included if written in English and focusing on technology that was or is difficult to implement. Results: Research suggests that the primary reason disruptive technology is not implemented sooner is the cost versus benefit ratio. Those technologies with extremely high benefits that greatly improve efficiency, safety, or expense are integrated relatively quickly, especially if their cost is reasonable. Secondary reasons for difficulty with integration include ethical dilemmas, extreme complexity, technical limitations, maintenance, security, and fallibility. Conclusion: Research indicates that a decrease in production cost and selling price along with removing any issues that may depreciate the technology will provide better incentives for healthcare systems to integrate disruptive technologies on a wider scale.

Background & Aims: Despite advances in surgical care and chemotherapeutic regimens, the five-year survival rate for Stage IV Hepatoblastoma (HB), the predominant pediatric liver tumor, remains at 27%. YAP1 and β-Catenin co-activation occurs in 80% of children’s HB; however, a lack of conditional genetic models precludes exploration of tumor maintenance and therapeutic targets. Thus, the clinical need for a targeted therapy remains unmet. Given the predominance of YAP1 and β-catenin activation in children’s tumors, I sought to evaluate YAP1 as a therapeutic target in HB. Approach & Results: Herein, I engineered the first conditional murine model of HB using hydrodynamic injection to deliver transposon plasmids encoding inducible YAP1S127A, constitutive β-CateninDelN90, and a luciferase reporter to murine liver. Tumor regression was evaluated using in vivo bioluminescent imaging, and tumor landscape characterized using RNA sequencing, ATAC sequencing and DNA foot-printing. Here I show that YAP1 withdrawal in mice mediates >90% tumor regression with survival for 230+ days. Mechanistically, YAP1 withdrawal promotes apoptosis in a subset of tumor cells and in remaining cells induces a cell fate switch driving therapeutic differentiation of HB tumors into Ki-67 negative “hbHep cells.” hbHep cells have hepatocyte-like morphology and partially restored mature hepatocyte gene expression. YAP1 withdrawal drives formation of hbHeps by modulating liver differentiation transcription factor (TF) occupancy. Indeed, tumor-derived hbHeps, consistent with their reprogrammed transcriptional landscape, regain partial hepatocyte function and can rescue liver damage in mice. Conclusions: YAP1 withdrawal, without modulation of oncogenic β-Catenin, significantly regresses hepatoblastoma, providing the first in vivo data to support YAP1 as a therapeutic target for HB. Modulating YAP1 expression alone is sufficient to drive long-term regression in hepatoblastoma because it promotes cell death in a subset of tumor cells and modulates transcription factor occupancy to reverse the fate of residual tumor cells to mimic functional hepatocytes.