Medicine and Health Sciences Commons^™

Modulation Of The Receptor Gating Mechanism And Allosteric Communication In Ionotropic Glutamate Receptors, Nabina Paudyal, Nabina Paudyal

Dissertations & Theses (Open Access)

Ionotropic glutamate receptors (iGluRs) found in mammalian brain are primarily known to mediate excitatory synaptic transmission crucial for learning and memory formation. The family of iGluRs consists of AMPA receptors, NMDA receptors and kainate receptors with each member having distinct physiological role. In the recent years, significant progress has been made in understanding the biophysical, and functional properties of iGluRs. The development of Cryo-EM and X-Ray crystallography techniques have further facilitated in the structural understanding of these receptors. However, the multidomain nature, large size of the protein, complex gating mechanism and inadequate knowledge regarding the conformational dynamics of the receptors …

Lgr5 Regulation Of Stat3 Signaling And Drug Resistance In Colorectal Cancer, Tressie Posey, Tressie Alexandra Posey

Dissertations & Theses (Open Access)

LGR5 Regulation of STAT3 Signaling and Drug Resistance in Colorectal Cancer

Tressie Alexandra Capri Posey B.S.

Advisory Professor: Kendra Carmon, Ph.D.

The greatest difficulty in treating colorectal cancer (CRC) is the development of drug resistance which leads to relapse after treatment and progression to metastasis. Cancer stem cells (CSCs) are believed to drive relapse because of their capacity to self-renew, acquire resistance mechanisms, and differentiate promoting tumor growth and heterogeneity. Leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5), is a bona-fide marker of CSCs and has been considered a viable target for CSC specific therapeutic development. While we showed targeting LGR5 …

Cross-Seeding Potential Of Misfolded Amyloid-Beta Strains On Tau Protein: Examining The Puzzle Pieces Of Alzheimer's Disease, Sara Kelley

Dissertations & Theses (Open Access)

Alzheimer’s disease (AD) is a neurodegenerative disorder that will progressively impair cognitive function. AD is the leading source of dementia, and affects one third of the senior citizens in the United States. Aging is the primary risk factor for AD and due to the expected rise in human lifespan worldwide, the occurrence rate of AD diagnosis is projected to increase. This observation is increasingly alarming when considering there is no treatment for reversal or prevention of AD yet.

AD is characterized by gross pathological hallmarks in the brain. These include the extracellular accumulation of misfolded amyloid-beta (Aβ) and the intraneuronal …

Agonist-Induced Conformational Changes In The Nmda Receptor, Ryan Durham, Ryan Durham

Dissertations & Theses (Open Access)

NMDA receptors are ligand-gated ion channels that mediate a number of physiological and pathological phenomena within the mammalian central nervous system. Under the typical course of activation, these receptors bind to glycine and glutamate molecules and undergo a series of conformational changes that results in the opening of a cation-permeable pore in the neuronal plasma membrane. Various aspects of NMDA receptor function are not fully understood, including the phenomenon of negative cooperativity between the glycine- and glutamate-binding sites of the receptor and the mechanism controlling partial agonism. Past studies utilizing static structural snapshots of the receptor or isolated domains of …

Mutant Kras Alters Extracellular Vesicle Microrna Sorting In Pancreatic Cystic Neoplasms, Rachel L. Dittmar

Dissertations & Theses (Open Access)

Pancreatic ductal adenocarcinoma (PDAC) is among the deadliest cancers by organ site with a 5-year survival rate of just 10.8%. This is largely because most patients do not experience symptoms until the disease has already metastasized. The best hope to cure PDAC is surgery, which can only be done with a curative intent at an early stage when the disease is localized. There are no reliable circulating, body-fluid-based biomarkers to detect early stage PDAC or its precursor lesions in a timely manner for effective surgical intervention. When potential PDAC precursor lesions, such as mucinous pancreatic cysts are found, there are …

Enhancing Adoptive Cell Therapy By Augmenting Fitness And Anti-Tumor Function Of Tumor-Infiltrating Lymphocytes, Parin Shah

Dissertations & Theses (Open Access)

The success of immune checkpoint inhibitors (ICIs) has established the importance of cancer immunotherapy in solid cancers, where it has been adopted as one of the standards of care for advanced melanoma and lung cancer. It is currently being investigated to treat other solid cancers. However, a large fraction of patients do not respond to ICIs and relapse. ICI therapy offers an in vivo approach to activate tumor-specific T cells, albeit in some cases, this modality does not create a sufficiently robust anti-tumor response. Thus, ex vivo approaches employing manipulation of immune cells, such as Adoptive Cell Therapy (ACT) using …

Mitochondrial Unfolded Protein Response Regulator Atf5 In Mitochondrial Targeted Therapies In Aml, Ran Zhao

Dissertations & Theses (Open Access)

Mitochondrial unfolded protein response (UPR^mt) is an adaptive transcriptional response induced by damaged proteins accumulated in mitochondria. UPR^mt signaling involves induction of mitochondrial specific chaperones and proteases such as HSP60, LonP1 and ClpP, aiding in the restoration of mitochondrial protein pool homeostasis. However, the cell-protective roles of UPR^mt in the context of mitochondrial stress-induced cell death in AML has not been well explored. We demonstrate that AML cells are susceptible to mitochondrial targeted agents such as ONC201, an agonist of the mitochondrial protease ClpP, and gamitrinib, an inhibitor of mitochondrial chaperone TRAP1, however, these agents also …

4d Ex Vivo Crispr/Cas9 Whole-Genome Screen To Identify Genes Regulating Lung Cancer Metastasis, Alexandria Plumer

Dissertations & Theses (Open Access)

Metastatic lung cancer has a 5-year survival rate of 5%. Lung cancers tend to be asymptomatic until late stages, and almost 90% are not diagnosed until they are advanced. Metastases are very rare events, often initiated by a single cell from a primary tumor into a new niche at a distant location. Investigation of the early metastatic process is of urgent need for the development of early diagnostics and targeted therapeutics. We performed a proof-of-concept CRISPR/Cas9 whole genome knockout screen in the A549 lung adenocarcinoma cell line and utilized a novel ex vivo 4D lung metastasis model to find gene …

The Src- And Abl- Dependent Regulation Of Net1a In Breast Cancer, Ashabari Sprenger

Dissertations & Theses (Open Access)

The neuroepithelial cell transforming gene 1 (Net1) is a RhoA guanine nucleotide exchange factor that promotes cancer cell motility and metastasis. Two isoforms of Net1 exist, Net1 and Net1A, both of which are which sequestered in the nucleus in quiescent cells to prevent aberrant RhoA activation. Many cell motility stimuli drive cytosolic relocalization of Net1A, but mechanisms controlling this event are not fully understood. Here we demonstrate that EGF stimulates Src- and Abl1-dependent phosphorylation of Net1A to promote its cytosolic localization. We find that Abl1 efficiently phosphorylates Net1A on Y373, and that phenylalanine substitution of Y373 prevents Net1A cytosolic localization. …

Atrx Inactivation And Idh1-R132h Drive Preferential Sensitivity To Proton Vs. X-Ray Radiotherapy In Glioma Stem Cells, Ángel Adrián Garcés

Dissertations & Theses (Open Access)

Background: Glioma Stem Cells (GSCs) are self-renewable, treatment resistant cells in the glioma tumor mass known to promote tumor development. In contrast to traditional photon-based radiation therapy (XRT), proton radiation therapy (PRT) may induce more complex DNA damage and therefore might have the potential to eliminate GSCs. Although previous studies have individually linked IDH mutations, specifically IDH1^R132H, and ATRX inactivating mutations to improved patient outcomes and suppressed DNA damage repair compared to their respective wild-types, the mechanisms by which these two genetic alterations interact in GSCs treated with PRT compared to XRT are currently unknown. We hypothesize that …

Deciphering The Role Of Hsp110 Chaperones In Diseases Of Protein Misfolding, Unekwu M. Yakubu

Dissertations & Theses (Open Access)

Molecular chaperones maintain protein homeostasis (proteostasis) by ensuring the proper folding of polypeptides. Loss of proteostasis has been linked to the onset of numerous neurodegenerative disorders including Alzheimer’s, Parkinson’s, and Huntington’s disease. Hsp110 is a member of the Hsp70 class of molecular chaperones and acts as a nucleotide exchange factor (NEF) for Hsp70, the preeminent Hsp70-family protein folding chaperone. Hsp110 promotes rapid cycling of ADP for ATP, allowing Hsp70 to properly fold nascent or unfolded polypeptides in iterative cycles. In addition to its NEF activity, Hsp110 possesses an Hsp70-like substrate binding domain (SBD) whose biological roles are undefined. Previous work …

Investigating Therapeutic Strategies To Target Metabolic Vulnerabilities Of Nsclc Tumors With Mutant Keap1 Gene, Pranavi Koppula

Dissertations & Theses (Open Access)

The metabolic vulnerability of cancers has long been envisaged as an attractive window to develop novel therapeutic strategies. Metabolic flexibility at the cellular level encompasses the efficient rerouting of anabolic and catabolic pathways in response to varying environmental stimuli to maintain cellular homeostasis and sustain proliferation. The primary objective of this study is to identify metabolic vulnerabilities bestowed by KEAP1/NRF2 signaling axis through SLC7A11. SLC7A11 is a transcriptional target of NRF2, an essential regulator of cellular anti-oxidant response. Under unstressed basal conditions, NRF2 interacts with KEAP1, a tumor suppressor gene and a substrate adaptor protein of the Cullin3-dependent ubiquitin ligase …

Secondary Use Of Structured Electronic Health Records Data: From Observational Studies To Deep Learning-Based Predictive Modeling, Laila Bekhet

Dissertations & Theses (Open Access)

With the wide adoption of electronic health records (EHRs), researchers, as well as large healthcare organizations, governmental institutions, insurance, and pharmaceutical companies have been interested in leveraging this rich clinical data source to extract clinical evidence and develop predictive algorithms. Large vendors have been able to compile structured EHR data from sites all over the United States, de-identify these data, and make them available to data science researchers in a more usable format. For this dissertation, we leveraged one of the earliest and largest secondary EHR data sources and conducted three studies of increasing scope. In the first study, which …

Enhance Representation Learning Of Clinical Narrative With Neural Networks For Clinical Predictive Modeling, Yuqi Si

Dissertations & Theses (Open Access)

Medicine is undergoing a technological revolution. Understanding human health from clinical data has major challenges from technical and practical perspectives, thus prompting methods that understand large, complex, and noisy data. These methods are particularly necessary for natural language data from clinical narratives/notes, which contain some of the richest information on a patient. Meanwhile, deep neural networks have achieved superior performance in a wide variety of natural language processing (NLP) tasks because of their capacity to encode meaningful but abstract representations and learn the entire task end-to-end. In this thesis, I investigate representation learning of clinical narratives with deep neural networks …

Assessing Sleep Efficiency Of Nulliparous Women In The Third Trimester Of Pregnancy, Ran Hu

Dissertations & Theses (Open Access)

Objectives: Pregnant women in the third trimester are more likely to experience sleep disorders, resulting in adverse effects on fetal health. This study aimed to evaluate the sleep efficiency (SE) of nulliparous women in their late pregnancy.

Methods: Data was extracted from the National Sleep Research Resource focusing on nulliparous women (n = 1,803) in their third trimester of pregnancy. The two-sample Wilcoxon test for continuous variables and the Chi-square test for categorical variables were used based on a normal SE cut-off of 0.85. The least absolute shrinkage and selection operator (Lasso) was used to find the risk …

Advancement Of A 3d Computational Phantom And Its Age Scaling Methodologies For Retrospective Dose Reconstruction Studies, Aashish Gupta

Dissertations & Theses (Open Access)

We have used a 3D age-scalable computational phantom for over two decades for retrospective dose reconstruction studies of childhood cancer survivors (CCS) treated with 2D historic radiotherapy (RT). However, our phantom and its age scaling functions (ASF) must be updated so that it can be used in studies that include survivors treated with contemporary RT. We aimed to implement our phantom and its age scaling functions in DICOM format and determine the feasibility of applying our ASFs to accurately scale the whole-body CT-based anatomies.

In the implementation study, we developed Python scripts that model the phantom and ASFs in a …

Modulating Immunometabolism To Improve The Activity Of Car-Nk Cells Targeting Cd70 In Renal Cell Carcinoma, Hind Rafei

Dissertations & Theses (Open Access)

Despite the approval of several therapies for metastatic clear cell renal cell carcinoma (ccRCC), disease resistance and relapse are common, and therapies with novel mechanisms of action are urgently needed. Chimeric antigen receptor (CAR) T-cell therapy has shown remarkable responses in hematologic malignancies, but many obstacles hinder success in solid tumors including the paucity of highly specific targets and the hostility of the tumor microenvironment (TME). Moreover, the limitations of generating an autologous cell product, such as cost of manufacture, and the challenges of toxicity with CAR-T cells highlight the need to develop new cell therapy products that are at …

Investigation Of Trophon® 2 For High Level Disinfection Of Rigid Endorectal Mri Coils, Rebecca Ditusa

Dissertations & Theses (Open Access)

Clinical Magnetic Resonance Imaging is most widely known for anatomical images with good image resolution and superb soft-tissue contrast. However, changes tumor metabolism may precede changes in gross size of the tumor. Newer studies present the use of 13C in MR imaging to interrogate tumor metabolism. With this additional information, not only can the size and makeup of a tumor be obtained, but also information about its metabolic characteristics. An increase in glucose uptake and production of lactate in the presence of oxygen—aerobic glycolysis—identifies abnormal metabolism, and hence a potential increase in tumor aggressiveness. Traditional 1H MRI of the prostate …

Identification And Targeting Of Downstream Ar-Camkk2-Mediated Mechanisms For The Treatment Of Advanced Prostate Cancer, Chenchu Lin

Dissertations & Theses (Open Access)

The androgen receptor (AR) is the primary driver of prostate cancer and, therefore, AR-regulated signaling events are essential for the development and progression of the disease. Despite their initial effectiveness, drugs targeting AR eventually fail as sustained inhibition of receptor activity remains a challenge. Previously, Ca²⁺/calmodulin-dependent protein kinase kinase 2 (CAMKK2) was identified as an essential downstream component of AR signaling in prostate cancer that correspondingly tracked with disease progression. While the importance of CAMKK2 in AR-mediated prostate cancer progression has been established, our understanding of the events downstream that promote the disease remains incomplete. Here, I elucidated …

Identification And Characterization Of De Novo Germline Tp53 Mutation Carriers In Families With Li-Fraumeni Syndrome, Carlos C. Vera Recio

Dissertations & Theses (Open Access)

Li-Fraumeni syndrome (LFS) is an inherited cancer syndrome caused by a deleterious mutation in TP53. An estimated 48% of LFS patients present due to a de novo mutation (DNM) in TP53. The knowledge of DNM status, DNM or familial mutation (FM), of an LFS patient requires genetic testing of both parents which is often inaccessible, making de novo LFS patients difficult to study. Famdenovo.TP53 is a Mendelian Risk prediction model used to predict DNM status of TP53 mutation carriers based on the cancer-family history and several input genetic parameters, including disease-gene penetrance. The good predictive performance of Famdenovo.TP53 was demonstrated …

Targeting Plasma Membrane Phosphatidylserine Content To Inhibit Oncogenic Kras Function, Walaa E. Kattan

Dissertations & Theses (Open Access)

The small GTPase KRAS, which is frequently mutated in human cancers, must be localized to the plasma membrane (PM) for biological activity. We recently showed that the KRAS C-terminal membrane anchor exhibits exquisite lipid-binding specificity for select species of phosphatidylserine (PtdSer). We therefore investigated whether reducing PM PtdSer content is sufficient to abrogate KRAS oncogenesis. Oxysterol-related binding proteins ORP5 and ORP8 exchange PtdSer synthesized in the ER for phosphatidylinositol-4-phosphate (PI4P) synthesized in the PM. We show that depletion of ORP5 or ORP8 reduced PM PtdSer levels, resulting in extensive mislocalization of KRAS from the PM. Concordantly, ORP5 or ORP8 depletion …

Standardizing New Diagnostic Tests To Facilitate Rapid Responses To The Covid-19 Pandemic, Xiao Dong

Dissertations & Theses (Open Access)

In order to enhance the data interoperability, an expeditious and accurate standardization solution is highly desirable for naming rapidly emerging novel lab tests, and thus diminishes confusion in early responses to pandemic outbreaks. This is a preliminary study to explore the roles and implementation of medical informatics technology, especially natural language processing and ontology methods, in standardizing information about emerging lab tests during a pandemic, thereby facilitating rapid responses to the pandemic. The ultimate goal of this study is to develop an informatics framework for rapid standardization of lab testing names during a pandemic to better prepare for future public …

Unveiling Global Roles Of G-Quadruplexes And G4-22 In Human Genetics, Ruth Barros De Paula

Dissertations & Theses (Open Access)

G-quadruplexes are non-B DNA structures formed by four or more runs of repeated guanines that confer unique features to living organism’s genomes. These sequences are enriched in regulatory regions, such as promoters and 5’ UTRs, and have distinct regulatory roles in both health and disease states. Even though previous studies showed the impact of G4 in gene expression, none of them summarized the location-specific effect of G4. Also, there is no broad understanding about the most common G4 repeat in the human genome, named here as G4-22, and how it links to the evolution of mammals and their biology. In …

Quantitative Magnetic Resonance Imaging For The Early Prediction Of Treatment Response In Triple Negative Breast Cancer, Benjamin C. Musall

Dissertations & Theses (Open Access)

Triple Negative Breast Cancer (TNBC) is an aggressive subtype of breast cancer which lacks upregulated hormone receptors. Because of this, it is not vulnerable to clinically available targeted therapies. When treated with standard of care neoadjuvant systemic therapy (NAST), TNBC only shows approximately a 40% rate of pathologic complete response (pCR). A biomarker which could predict TNBC response to NAST early during treatment would be useful, as it would allow for non-responders to be triaged to alternative therapies and potentially allow for the treatment of responders to be de-escalated.

Quantitative Magnetic Resonance Imaging (MRI) may be used to probe and …

Development Of Quantitative Molecular Photoacoustic Imaging For Noninvasive Cancer Diagnostics, Cayla Zandbergen

Dissertations & Theses (Open Access)

Traditional diagnostic imaging provides clinicians with anatomical information that guides both diagnosis and treatment planning; however, once a tumor has progressed enough to be visible, it has often reached an advanced stage. Molecular imaging techniques allow for real-time visualization of chemical and biological processes via imaging of specific biomarkers, which can facilitate detection of malignancies before they become visible. One biomarker of interest is blood oxygen saturation (SO₂) due to its correlation with hypoxia, which is associated with increased tumor malignancy; some studies have also established SO₂ as an independent biomarker of disease progression. Additionally, because cancerous …

Understanding The Pathogenesis Of Renal Medullary Carcinoma, Melinda Soeung

Dissertations & Theses (Open Access)

Renal medullary carcinoma (RMC) is a lethal cancer that predominantly affects young individuals with sickle cell trait (SCT). It is not currently understood why RMC only affects certain individuals with SCT. We found that patients with RMC more frequently participated in high-intensity exercise than matched controls. Using mouse models of SCT, we demonstrated the significant increase of renal hypoxia in the right kidney following high- but not moderate-intensity exercise. We also demonstrated in cell culture studies that SMARCB1 is ubiquitinated for proteasome-mediated degradation in hypoxia, and the re-expression of SMARCB1 leads to compromised proliferation in renal cells specifically in the …

Dissecting Tumor Heterogeneity In Lung Cancer, Aparna Padhye

Dissertations & Theses (Open Access)

Lung cancer is a heterogeneous disease composed of genetically and phenotypically distinct tumor cells as well as a heterogeneous microenvironment consisting of non-cancer cells and extracellular matrix. Constant interactions among these components ultimately leads to a complex tumor tissue that is ever evolving and poses a therapeutic challenge for sustained benefit. Strategies for targeting lung cancers are largely guided by the genetic alterations identified in the tumor specimens. However, in order to gain a better understanding of lung cancer progression and develop effective treatment modalities, studying tumor in context of its microenvironment is crucial. The first aim of this project …

Intranasal Hpv Peptide Vaccine Formulation Induces Potent Cytotoxic Cd8 T Cell Immunity For The Treatment Of Genital Hpv Tumors, Gloria Sierra

Dissertations & Theses (Open Access)

Human Papillomavirus (HPV) induced cancers continue to affect millions of women worldwide, with the five year survival rate hovering just under 60% in some demographics. Therefore there is an unmet need to develop effective, yet, easily administered therapies to treat established HPV genital lesions. Even though immune checkpoint therapy (ICT) is a promising treatment option in some HPV+ cancers, the high cost and associated toxicities are still major concerns for their widespread application. HPV cancers are textbook candidates for therapeutic vaccination intervention because they’re driven by the expression of viral oncoproteins E6 and E7, which serve as ideal tumor specific …

Micrornas As A Therapeutic Target To Regulate Microglial Activation In Post­ Stroke Isolation In Aged Male Mice, Anik Banerjee

Dissertations & Theses (Open Access)

Introduction:

It is increasingly recognized that social Isolation (SI) leads to a wide array of behavioral and cognitive deficits. Isolation and loneliness are linked to all-cause mortality, as well as mortality from stroke and other vascular diseases. In addition, isolated or lonely individuals have significantly poorer cognitive and functional outcomes following stroke and have higher rates of stroke recurrence. These detrimental effects have also been recapitulated in animal models; animals isolated prior to, or at the time of stroke, have larger infarcts than pair-housed mice. However, the mechanisms mediating the effects of social factors on stroke recovery are unknown. An …

Synthetic Essentiality Of Tdo2 In Apc-Mutated Colorectal Cancer, Rumi Lee

Dissertations & Theses (Open Access)

Inactivation of the adenomatous polyposis coli (APC) tumor suppressor is

common genetic event across many cancers and serves a critical initiating

event in the majority of sporadic colorectal cancers (CRC). The WNT/APC

pathway remains an elusive target for cancer, prompting us to explore

orthogonal strategies to identify specific vulnerabilities for APC-deficient

CRC and other cancers. Using the concept of synthetic essentiality (SE), we

sought to identify essential effectors of APC deficiency with the goal of

expanding targetable vulnerabilities in CRC. We identified Tryptophan 2,3-

dioxygenase 2 (TDO2) as an SE gene for APC-deficient cancers.

Mechanistically, APC loss results in TCF4/b-catenin-mediated …