Life Sciences Commons^™

Modulating Hallmarks Of Cholangiocarcinoma, Cody Wehrkamp

Theses & Dissertations

How are cholangiocarcinoma cells different from non-malignant cholangiocytes?

All of the hallmarks of cancer apply- those reported in this dissertation include cell proliferation, migration, apoptosis, and evasion of growth suppression. My studies began with testing how apoptosis might be regulated through embelin, a small molecule reported to sensitize cells to apoptosis by blocking XIAP. My data however revealed that embelin reduced the proliferative capacity in cholangiocarcinoma cells, but did not increase cell death. Malignant cells exhibit dysregulation of microRNA processing and expression. Hence, my studies seeking ways that cholangiocarcinoma eludes apoptosis transitioned to the oncomiR miR-106b, which is overexpressed in …

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 …

Development Of Chloroquine-Containing Hpma Copolymers For Drug Delivery, Fei Yu

Theses & Dissertations

Abstract

Development of Chloroquine-containing HPMA Copolymers for Drug Delivery

Fei Yu, Ph.D.

University of Nebraska Medical Center, 2018

Supervisor: David Oupický, Ph.D.

Synthetic polymers have been extensively explored for improved delivery of anticancer agents. Polymers can be designed as either carriers of existing drugs or as polymeric drugs with intrinsic pharmacological activity. Advantages of such polymeric drugs include common positive features of polymer-drug conjugates, such as targeted delivery of drugs, altered pharmacokinetic and biodistribution, improved drug safety, but also favorable pharmacological activities due to multivalent receptor-ligand interactions.

Chloroquine (CQ) and hydroxychloroquine (HCQ) are safe drugs that have been in clinical …

Neuronal And Glial Expression Of Glun2c And Glun2d Nmda Receptor Subunit Mrna In Different Regions Of The Mouse Forebrain, Hassan Alsaad

Theses & Dissertations

N-methyl-D-aspartate (NMDA) receptors are a subtype of glutamate receptors that are widely expressed in the brain, where they mediate critical functions. While the actions of the predominate GluN2 NMDAR subunits, GluN2A and GluN2B are relatively well understood, the function of GluN2C and GluN2D in the telencephalon is largely unknown. To better understand the possible role of GluN2C and GluN2D subunits, we used fluorescence in situ hybridization together with multiple cell markers to define the distribution and type of cells expressing GluN2C and GluN2D mRNA. Also, a GluN2C-KO mouse was used as a negative control.

GluN2C mRNA expression was only found …

Red Panda: A Novel Method For Detecting Variation In Single-Cell Rna Sequencing, Adam Cornish

Theses & Dissertations

Single-cell sequencing enables the rapid acquisition of genomic and transcriptomic data from individual cells to better understand genetic diseases, such as cancer or autoimmune disorders, which are often affected by changes in rare cells. Currently, no existing software is aimed at identifying single nucleotide variations or micro (1-50bp) insertions and deletions in single-cell RNA sequencing (scRNA-seq) data. However, generating high quality data is vital to the study of the aforementioned diseases, among others. Our goal is to create such a tool and use in-house sequencing to validate its effectiveness. Our software employs the unique information found in scRNA-seq data to …

Delineation Of New Mechanisms Of Dna Double Strand Break Repair, Songli Zhu

Theses & Dissertations

DNA damage is frequently induced in cells by both endogenous and exogenous agents. DNA damage, particular double strand breaks (DSBs) may lead to genomic instability, and the progression of cancer, aging, neurodegeneration, and other human diseases. The cell employs two major DSB repair pathways, including homologous recombination (HR) and Non-homologous end joining (NHEJ), but the detailed mechanisms of DSB repair remain to be further revealed.

In the first part of this study, we characterized a plasmid-based assay to investigate NHEJ repair in Xenopus egg extracts. Our data argued for a preference for the precise repair by the NHEJ machinery and …

Intra- And Inter-Molecular Signaling In A Cardiac Connexin: Role Of Cytoplasmic Domain Dimerization And Phosphorylation, Andrew J. Trease

Theses & Dissertations

As critical mediators of cell-to-cell communication, gap junctions (GJs) are comprised of membrane channels that directly link the cytoplasm of adjacent coupled cells thereby allowing for the passage of ions, small metabolites, and secondary messengers. Each channel is formed by the apposition of two connexons from adjacent cells, each composed of six connexin (Cx) proteins. Each GJ channel functions to promote signal propagation and synchronization of cells and tissues in organs. Furthermore, GJs are essential for proper propagation of cardiac action potentials from one cell to the next, leading to the coordinated contraction and relaxation of heart muscle powering circulation. …

Towards An In Vitro Model Of Testing Osteoblast Cellular Function In Contact With Various Surfaces, Raheleh Miralami

Theses & Dissertations

Past studies have shown that the success of total joint replacements depends on the biocompatibility of orthopaedic materials, which can be improved by modifying the implant surface. However, the exact roles of these modifications and their effective mechanisms are poorly understood. The objective of this study was to develop and evaluate a model system to investigate the impact of nano-structured surfaces, produced by the ion beam-assisted deposition (IBAD) technique, on biomarkers of osteointegration using an in vitro model. The IBAD technique was employed to deposit zirconium oxide (ZrO₂), Titanium oxide (TiO₂), and Titanium (Ti) nano-films on …

The Opposing Roles Of Glun2c And Glun2d Nmda Receptor Subunits In Modulating Neuronal Oscillations, Zhihao Mao

Theses & Dissertations

N-methyl-D-aspartate receptors (NMDARs) are ligand-gated ion channels consisting of two GluN1 subunits and two other subunits from among GluN2A-2D and GluN3A-3B subunits. NMDARs play critical roles in synaptic plasticity, learning and memory, and higher brain function such as cognition and perception. Dysfunction of NMDARs (hyper-function and hypo-function of NMDARs) are related to various diseases, including stroke, schizophrenia, Alzheimer’s disease, and others. However, to date, NMDARs antagonists have mostly failed in clinical trials due to adverse effects.

NMDARs antagonists replicate the core symptoms of schizophrenia which may underlie its ability to alter neuronal oscillations in the neural circuitry of different brain …

Functional And Mechanical Role Of Splice Variant Of Mucin4 (Muc4/X) And Trefoil Factors In Pancreatic Cancer Pathogenesis, Rahat Jahan

Theses & Dissertations

Pancreatic Cancer (PC) is one of the vicious cancers as it ranks third in the race of leading cause of cancer-related death. Lack of early diagnostic marker, poor understanding of molecular mechanism of the disease and failure to conventional chemotherapy makes this disease dreadful.

Mucin 4 (MUC4), a high molecular weight glycoprotein is one of the top differentially expressed molecules in PC while not expressed in normal pancreas. Accumulating evidence from our lab suggested its tumorigenic role in PC by increasing cell proliferation, invasion, chemotherapy resistance, tumor growth, and metastasis. Previously, our lab and other has identified 24 different splice …

Transcriptional Regulation Of Icaadbc By Icar And Tcar In Staphylococcus Epidermidis, Tramy Hoang

Theses & Dissertations

Biofilm formation is the primary virulence factor in Staphylococcus epidermidis. Polysaccharide intercellular adhesin (PIA) is an adhesive molecule and a significant component of the biofilm matrix. It is synthesized by the products of the icaADBC operon whose regulation has been shown to involve environmental factors as well as many transcriptional regulators. Of these regulators, we explored the function of the repressors IcaR and TcaR and their roles in directly influencing icaADBC transcription and PIA synthesis. Based on previous observations that icaADBC positive clinical isolates of S. epidermidis are highly variable in PIA synthesis and biofilm formation, our goal was to …

An Evaluation Of The Use Of A Clinical Research Data Warehouse And I2b2 Infrastructure To Facilitate Replication Of Research, Bret Gardner

Theses & Dissertations

Replication of clinical research is requisite for forming effective clinical decisions and guidelines. While rerunning a clinical trial may be unethical and prohibitively expensive, the adoption of EHRs and the infrastructure for distributed research networks provide access to clinical data for observational and retrospective studies. Herein I demonstrate a means of using these tools to validate existing results and extend the findings to novel populations. I describe the process of evaluating published risk models as well as local data and infrastructure to assess the replicability of the study. I use an example of a risk model unable to be replicated …

Arid1b And Macf1 In Murine Brain Development And Behavior, Jeffrey Jay Moffat

Theses & Dissertations

Intellectual disability (ID) and autism spectrum disorder (ASD) affect between one and three percent of the global population. These disorders represent a significant emotional and financial burden for affected individuals and their families. Treatment for these conditions remains limited because many of the key molecular factors and associated pathogenic mechanisms are still poorly understood.

In this report we examine two genes related to ASD and ID, AT-rich interactive domain-containing protein 1B (ARID1B) and Microtubule-actin crosslinking factor 1 (MACF1). ARID1B is a subunit of the mammalian BRG1/BRM associated factor (BAF) chromatin-remodeling complex, which broadly regulates gene expression. ARID1B also …

Development Of Macromolecular Prodrug Conjugates For The Diagnosis And Treatment Of Musculoskeletal Diseases, Xin Wei

Theses & Dissertations

Macromolecular prodrug conjugate is a promising strategy for better diagnosis and treatment of musculoskeletal diseases. Our lab has pioneered this effort and has successfully developed multiple prodrug formulations. The general approach we have taken is to incorporate active ingredient (AI, including imaging probe or therapeutic agents) containing monomers into water-soluble and biocompatible polymers, such as N-(2-Hydroxypropyl) methacrylamide (HPMA) copolymers. Structural parameters of these polymeric prodrugs, such as molecular weight (MW), drug loading, prodrug activation mechanism and the selection of drug payload may greatly affect therapeutic efficacy and the safety of the macromolecular prodrugs. To investigate the impact of these …

Foxm1 Expression And Contribution To Genomic Instability And Chemoresistance In High-Grade Serous Ovarian Cancer, Carter J. Barger

Theses & Dissertations

High-grade serous ovarian cancer (HGSC) is the most common and deadly subtype of epithelial ovarian cancer. Understanding the molecular basis of HGSC will improve diagnosis and treatment approaches. The Cancer Genome Atlas (TCGA) discovered that Forkhead Box M1 (FOXM1) transcription factor activation is the second most frequent molecular alteration in HGSC (84% of cases), second only to mutations of TP53 (100%). We subsequently defined several genetic mechanisms that underlie increased FOXM1 expression in HGSC, including genomic amplifications and RB-E2F deregulation, and showed that FOXM1 promotes cell cycle progression in cell models relevant to HGSC.

TCGA analyses revealed that genomic instability, …

Neural Correlates Of Polysubstance Use: Differential And Interactive Effects Of Alcohol And Cannabis On The Adolescent Brain, Joseph Aloi

Theses & Dissertations

Two of the most commonly used and abused substances by adolescents in the United States are alcohol and cannabis, which are associated with adverse medical and psychiatric outcomes. Alcohol use and cannabis use during adolescence is also associated with an increased risk of alcohol use disorder (AUD) and/or cannabis use disorder (CUD) in adulthood as well as increased likelihood of relapse after successful treatment. Despite this, much of the previous work on the neurobiology of substance use disorders has focused on adult substance use. This work has shown that individuals with AUD and/or CUD show dysfunction within reward processing, emotion …

Molecular Mechanism Of Early Amyloid Self-Assembly Revealed By Computational Modeling, Mohtadin Hashemi

Theses & Dissertations

Protein misfolding followed by the formation of aggregates, is an early step in the cascade of conformational changes in a protein that underlie the development of several neurodegenerative diseases, including Alzheimer’s and Parkinson’s diseases. Efforts aimed at understanding this process have produced little clarity and the mechanism remains elusive.

Here, we demonstrate that the hairpin fold, a structure found in the early folding intermediates of amyloid b, induces morphological and stability changes in the aggregates of Aβ(14-23) peptide. We structurally characterized the interactions of monomer and hairpin using extended molecular dynamics (MD) simulations, which revealed a novel intercalated type complex. …

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 …

Elucidating The Roles Of Lunatic Fringe In Pancreatic Ductal Adenocarcinoma, Prathamesh Patil

Theses & Dissertations

Pancreatic cancer is an aggressive form of cancer that is very difficult to detect, treat resulting in a high rate of mortality. Understanding the molecular basis of pancreatic cancer and identifying new molecular targets for designing therapeutic interventions is paramount for improving outcomes in this disease. Notch signaling is a vital developmental signaling pathway that has been implicated to play both oncogenic and tumor suppressive roles in pancreatic cancer. Previous studies from other groups have shown that O-linked glycosylation of Notch signaling plays a key role in the regulation of Notch signaling. Lunatic fringe (Lfng) is one of the glycosyltransferases …

Functional Role Of Protein Kinase C Alpha In Endometrial Carcinogenesis, Alice Hsu

Theses & Dissertations

Protein kinase Cα (PKCα) is a member of the PKC family of serine/threonine kinases that regulate many fundamental cellular processes, including cell proliferation, differentiation, survival and transformation. The impact of PKCα on tumorigenesis, and whether it acts as an oncogene or tumor suppressor, has been debated over the years. The overall goal of this study was to establish the functional role of PKCα in endometrial carcinogenesis. Results from this study broaden our knowledge of PKCα signaling and add to our understanding of its role in tumor development.

As understanding of the role of PKCα signaling in the uterus is limited, …

Overcoming Tcf4-Driven Bcr Signaling In Diffuse Large B-Cell Lymphoma, Keenan Hartert

Theses & Dissertations

Diffuse Large B-cell Lymphoma (DLBCL) is the most common subtype of lymphoma. Despite a cure rate of 40% with standard R-CHOP therapy, patients that refract or relapse are subject to a dismal prognosis. Cases of DLBCL can be classified by their molecular expression phenotype, with the GCB-like subtype aligning with the profile of a germinal center B-cell and the ABC-like subtype aligning to that of an activated B-cell. Aggressive disease is often characterized by high levels of B-cell Receptor (BCR) signaling. This pathway engages downstream kinases responsible for stimulating proliferation and survival that play a key role under the normal …

T Cell Mediated Cytotoxicity In The Mptp Mouse Model Of Parkinson's Disease, Rebecca A. Wilshusen

Theses & Dissertations

Increasing evidence suggests that neurotoxic inflammatory activities affect the pathogenesis and progression of PD. Neuroinflammatory processes also produce oxidized and modified self-central nervous system (CNS) proteins which lead to dysfunction, mis-folding, aggregation, and retention of those oxidized products. In PD, nitrated α-synuclein (N-α-syn) is found aggregated within the cytoplasm and Lewy bodies of dopaminergic neurons within the substantia nigra and is released to the extraneuronal environment by dying and damaged neurons. Previous studies have shown that after 1-methyl 4-phenyl 1,2,3,6-tetrahydropyridine (MPTP) intoxication, adoptive transfer of effector T cells (Teff) exacerbates microglial-mediated neuroinflammation and amplifies dopaminergic neurodegeneration with accelerated and prolonged …

Connexin32: Sorting, Endocytosis And Assembly, Anuttoma Ray

Theses & Dissertations

Gap junctions (GJ)s are conglomeration of several cell-cell channels at cell-to-cell contact sites involved in the direct intercellular exchange of small growth regulatory molecules. Defects in assembly of GJ-forming proteins, called connexins (Cxs), are observed in many cancers, yet the molecular basis of this defect remains unknown. Connexin32 (Cx32) is expressed by the polarized cells in epithelia. The carboxyl-terminal tail (CT) of Cx32, although not required to initiate GJ formation, orchestrates several aspects of GJ dynamics, function and growth. Our studies have discovered that the CT of Cx32 harbors a tyrosine-based [YXXØ]-type and two dileucine-based [DE]XXXL[LI]-type motifs, which govern the …

Elucidation Of The Functions Of Neuropilin 2 In Osteoclasts In Promoting Prostate Cancer Bone Metastasis., Navatha S. Polavaram

Theses & Dissertations

Bone metastasis is one of the major clinical concerns that causes skeletal related malignancies and increased mortality. Bone is one of the preferred sites for metastatic prostate cancer. The metastatic prostate cancer cells interact with bone cells (osteoblasts and osteoclasts) resulting in an imbalance in the bone homeostasis leading to increased activation of osteoblasts over osteoclasts. Our preliminary data indicated a non-tyrosine kinase receptor Neuropilin 2 (NRP2) is expressed in osteoclasts induced by metastatic prostate cancer cells and acts as a negative regulator of osteoclast differentiation and function. We hypothesize that prostate cancer -induced NRP2 expression in osteoclasts is necessary …

Inhibition Of Rad52-Based Dna Repair For Cancer Therapy, Mona Al-Mugotir

Theses & Dissertations

Germline BRCA mutations underlay a significant risk for breast and ovarian cancer that increases in age. BRCA mutations are usually associated with the most aggressive subtypes of these cancers such as triple negative breast cancer and high-grade serous ovarian cancer. Conventional chemotherapeutic or hormonal therapies do not address the molecular deficiencies responsible for their resistance and there is a high rate of recurrence. Targeted therapy that can address the unique molecular features in these subtypes of cancer is the only way to cure the disease or, at the very least, improve patients’ quality of life.

Homologous recombination repair is an …

The Role Of Hippo Pathway In Mitosis And Cancer, Xingcheng Chen

Theses & Dissertations

The Hippo signaling pathway has been recently elucidated as a tumor suppressor pathway controlling cell proliferation and apoptosis. The core of this pathway is a kinase cascade which 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). MST1/2 transduce their kinase activity mainly through directly phosphorylating LATS1/2. Once phosphorylated and activated, LATS1/2 subsequently phosphorylate and inhibit YAP from translocating to nucleus. Current studies involving the Hippo pathway focus on determining its oncogenic role in various organs/tissues. While those studies provide important insight into the tumor suppressor properties of this pathway, …

The Beta-Catenin/Muc1.Ct Interaction In Pancreatic Cancer, Edwin Wiest

Theses & Dissertations

MUC1 is overexpressed in over 90% of pancreatic cancer cases, and its interaction with beta-catenin promotes progression of the disease. Various in vitro and in vivo methods show that beta-catenin and MUC1 interact by way of the cytoplasmic tail of MUC1 (MUC1.CT). This interaction occurs in the membrane of pancreatic cancer cells but is found to a smaller extent in the nucleus as well. Biophysical methods suggest that MUC1 interacts with beta-catenin through a sequence of amino acids in the tail of MUC1 that sit very near the transmembrane domain of MUC1. In pancreatic ductal adenocarcinoma cells, it appears that …

Mechanisms For The Potassium Sparing Effects Of Furosemide In Mice On High Potassium Diets, Bangchen Wang

Theses & Dissertations

Because of its cardio-protective benefits, diets that are low in Na⁺ and high in K⁺ are often warranted in conjunction with use of diuretics such as furosemide for treating hypertension. It is critical to understand how such diets influence the diuretic actions on renal K⁺ handling in order to choose the best drug for patients.

Furosemide is a commonly used K-wasting diuretic. It increases urinary K⁺ excretion by increasing distal Na⁺ delivery that stimulates K⁺ secretion. However, in wild-type mice (WT) adapted to an alkaline low Na⁺ high K⁺ diet (LNaHK), both …

Muc4 Based Immunotherapy For Pancreatic Cancer, Kasturi Banerjee

Theses & Dissertations

Pancreatic Cancer (PC) is a lethal disease claiming approximately 45000 lives in the US in 2018, and it establishes an elaborate immunosuppressive tumor microenvironment that aids in disease pathogenesis. Immunotherapy has emerged as a strategy to target tumor cells by reprogramming patient’s immune system. Challenges present in PC immunotherapy are: i) identifying a tumor-associated antigen that could be targeted, ii) identifying adjuvants that could efficiently deliver antigens, iii) eliciting robust anti-tumor responses and iv) overcoming peripheral tolerance and immunosuppression elicited by the tumor.

Firstly, we detected circulating autoantibodies to MUC4 present in PC patients and observed that IgM autoantibodies to …

Francisella Tularensis Insertion Sequence Elements Contribute To Differential Gene Expression, Amanda M. Bartling

Theses & Dissertations

This abstract is under embargo until April 26, 2020.