Life Sciences Commons^™

Statistical Methods For Two Problems In Cancer Research: Analysis Of Rna-Seq Data From Archival Samples And Characterization Of Onset Of Multiple Primary Cancers, Jialu Li

Dissertations and Theses (Open Access)

My dissertation is focused on quantitative methodology development and application for two important topics in translational and clinical cancer research.

The first topic was motivated by the challenge of applying transcriptome sequencing (RNA-seq) to formalin-fixation and paraffin-embedding (FFPE) tumor samples for reliable diagnostic development. We designed a biospecimen study to directly compare gene expression results from different protocols to prepare libraries for RNA-seq from human breast cancer tissues, with randomization to fresh-frozen (FF) or FFPE conditions. To comprehensively evaluate the FFPE RNA-seq data quality for expression profiling, we developed multiple computational methods for assessment, such as the uniformity and continuity …

Molecular Mechanisms Of Inward And Outward Budding From Multivesicular Endosomes, Monica Gireud Goss

Dissertations and Theses (Open Access)

Regulating the residence time of membrane proteins (e.g. transporters, ion channels, receptors) on the cell surface can modify their response to extracellular cues and allow for cellular adaptation to environmental conditions. The fate of membrane proteins that are internalized from the plasma membrane and arrive at the limiting membrane of the late endosome/multivesicular body (MVB) is dictated by whether they remain on the limiting membrane, bud into internal MVB vesicles, or bud outwardly from the membrane. The molecular details underlying the disposition of membrane proteins that transit this pathway and the mechanisms regulating these trafficking events are unclear. We established …

The Role Of The Diras Family Members In Regulating Ras Function, Cancer Growth And Autophagy, Margie Nicole Sutton

Dissertations and Theses (Open Access)

DIRAS3 is a maternally imprinted tumor suppressor gene that is downregulated by multiple mechanisms across several tumor types. When re-expressed, DIRAS3 decreases proliferation, inhibits motility, and induces autophagy and tumor dormancy. DIRAS3 encodes a 26 kDa small GTPase with 60% homology to Ras and Rap, differing from oncogenic Ras family members by a 34-amino acid N-terminal extension that is required for its tumor suppressive function in ovarian cancer. By assessing the structure-function relationship, I found that DIRAS3 inhibits Ras-induced transformation and is a natural antagonist of Ras/MAPK signaling. DIRAS3 binds directly to Ras and disrupts cluster formation inhibiting the activation …

Androgen Receptor And Prostate Cancer Cell Heterogeneity, Qu Deng

Dissertations and Theses (Open Access)

Androgen receptor (AR) plays an important role in prostate cancer (PCa) development and has been the main therapeutic target in advanced PCa. AR expression is heterogeneous in both primary PCa and castration resistant prostate cancer (CRPC). However, the functional significance of AR heterogeneity in regulating PCa biology and response to androgen/AR-targeted therapies remains unclear. The overarching hypothesis for my Ph.D is that AR heterogeneity contributes to PCa development, progression, and therapy resistance. A more specific postulate is that PCa cells expressing AR (i.e, AR⁺) and PCa cells expressing little AR (i.e, AR^-/lo) possess intrinsically distinct …

Proteomic Identification Of Histone Post-Translational Modifications Induced By Dna Double-Strand Breaks And Novel Proteins Involved In The Dna Damage Response, Pingping Wang

Dissertations and Theses (Open Access)

Inaccurate repair of DNA double-strand breaks (DSBs) can lead to DNA mutation and chromosome rearrangements, causing human diseases such as cancer. Although we know the basic mechanisms of DSB repair, the added complexities in the chromatin context are unclear. This is partially due to the lack of unbiased systems for identifying proteins and post-translational modifications (PTMs) involved in DSB repair. In this work, we established a novel method, termed DSB-ChAP-MS (Double Strand Break-Chromatin Affinity Purification with Mass Spectrometry), for the affinity purification of a sequence-specific single copy endogenous chromosomal locus containing a DSB, followed by the proteomic identification of enriched …

Fret-Based Investigations Of The Structure-Function Relationships In The Nmda Receptor, Drew M. Dolino

Dissertations and Theses (Open Access)

The N-methyl-D-aspartate (NMDA) receptor is one member of a class of proteins known as the ionotropic glutamate receptors. Ionotropic glutamate receptors mediate the majority of excitatory neurotransmission in the central nervous system, with the NMDA receptor standing out among these receptors for its requirement of a co-agonist, its magnesium-block-based coincidence detection, its slow kinetics, its calcium permeability, its allosteric modulation, and its especially important functional roles in synaptic plasticity, excitotoxicity, and more. In recent years, a wealth of structural information has come about describing endpoint structures to high resolution, but such structures are unable to fully resolve the movements …

Non-Coding Rnas Identify The Intrinsic Molecular Subtypes Of Muscle-Invasive Bladder Cancer, Andrea E. Ochoa

Dissertations and Theses (Open Access)

NON-CODING RNAS IDENTIFY THE INTRINSIC MOLECULAR SUBTYPES OF MUSCLE-INVASIVE BLADDER CANCER

Andrea Elizabeth Ochoa, B.S.

Advisory Professors: David J. McConkey, Ph.D. and Joya Chandra, Ph.D.

There has been a recent explosion of genomics data in muscle-invasive bladder cancer (MIBC) to better understand the underlying biology of the disease that leads to the high amount of heterogeneity that is seen clinically. These studies have identified relatively stable intrinsic molecular subtypes of MIBC that show similarities to the basal and luminal subtypes of breast cancer. However, previous studies have primarily focused on protein-coding genes or DNA mutations/alterations.

There is emerging evidence implicating …

Characterization And Reversal Of Doxorubicin-Mediated Changes In Sensory Neurons, Brittany L. Coughlin

Dissertations and Theses (Open Access)

Chemotherapeutic agents impair memory in humans as well as in animal models. Such memory impairments can be persistent, lasting years after exposure to chemotherapy. Doxorubicin (DOX), a common chemotherapeutic agent, has been associated with memory impairments in humans and induces memory deficits in rodent models. DOX also impairs serotonin (5-HT)-induced long-term synaptic facilitation (LTF) in Aplysia sensorimotor co-cultures, a cellular analog of long-term memory formation. In addition, DOX leads to dynamic activation of extracellular signal-regulated kinase (ERK), consisting of an immediate and a delayed phase of activation, and to transient activation of p38 mitogen-activated protein kinase (p38 MAPK) in Aplysia …

Evaluating The Impact Of Post-Translational Modifications By The Secreted Zinc Metalloprotease, Gele, On The Major Autolysin Of E. Faecalis, Atla, And A Stress-Induced Protein, Salb, Emily K. Stinemetz

Dissertations and Theses (Open Access)

AtlA is the major peptidoglycan hydrolase of E. faecalis involved in cell separation of dividing cells. SalB is a secreted stress-induced protein regulated by the CroRS system. In addition, these two proteins also appear to be affected by the virulence factor, gelatinase (GelE). GelE is a secreted zinc metalloprotease known to impact various cellular functions by post- translational modification of protein substrates. The overall objective of this work was to understand how GelE cleavage of secreted proteins, specifically AtlA and SalB, changes their function. Herein, I discovered that GelE modifies both AtlA and SalB. As visualized by Western blot analysis …

On The Origin Of Sensory Errors, Jonathan R. Flynn

Dissertations and Theses (Open Access)

Estimation of perceptual variables is imprecise and prone to errors. Although the properties of these perceptual errors are well characterized, the physiological basis for these errors is unknown. One previously proposed explanation for these errors is the trial-by-trial variability of the responses of sensory neurons that encode the percept. Initially, it would seem that a complicated electrophysiological experiment would need to be performed to test this hypothesis. However, using a strong theoretical framework, I demonstrate that it is possible to determine statistical characteristics of the physiological mechanism responsible for perceptual errors solely from a behavioral experiment. The basis for this …

Attitudes To Ward And Uptake Of Prenatal Genetic Screening And Testing In Twin Pregnancies, Kathryn M. Reese

Dissertations and Theses (Open Access)

The rate of twinning is rising and is associated with delayed age at childbirth and increased infertility treatments. Since the introduction of non-invasive prenatal testing, interest in and uptake of genetic screening and testing in twin pregnancies has not been investigated. Therefore, this study aimed to describe the attitudes toward and uptake of current prenatal genetic screening and testing options in twin pregnancies. Forty-two women with twin gestations were recruited from UTHealth and Baylor College of Medicine sites between August 2016 and January 2017 for participation in a descriptive study consisting of a questionnaire (n=42) and semi-structured phone interview (n=15). …

Investigation Of The Roles Of Asf1 And Caf-1-Mediated Chromatin Assembly In The Human Dna Damage Response, Ting-Hsiang Huang

Dissertations and Theses (Open Access)

The access-repair-restore model for the role of chromatin in DNA repair infers that chromatin is a mere obstacle to DNA repair. However, here we show that blocking chromatin assembly of newly-synthesized histones, via knockdown of the histone chaperones ASF1A, CAF-1 or a mutation that specifically prevents ASF1 binding to histones, hinders loading of Rad51 onto ssDNA during homologous recombination, as a consequence of reduced recruitment of the Rad51 loader MMS22L/TONSL to ssDNA, resulting in persistent RPA foci, extensive DNA end-resection, and persistent activation of the ATR-Chk1 pathway. By contrast, ASF1 and CAF-1 render the rapid inactivation of ATM Chk2 pathway …

Developing Novel Approaches To Improve Response To T Cell Based Cancer Immunotherapy, Rina M. Mbofung

Dissertations and Theses (Open Access)

Recently, T cell based immunotherapies have moved to the forefront of cancer immunotherapy with the success of Adoptive T cell therapy (ACT) and Immune checkpoint blockade.ACT, where patients are treated with tumour infiltrating T cells (TILs), conferred a clinical response rate of ~50%. Treatment with anti-CTLA4 and anti –PD1 therapy, conferred response rates of up to 50%, greatly improving the overall survival of patients with advanced melanoma amongst other cancer types. Despite the encouraging outcomes, there are relatively low response rates coupled with the delay of weeks to months before tumour shrinkage can be appreciated. Thus, understanding what tumour intrinsic …

The Utilization Of Prenatal Microarray: A Survey Of Current Genetic Counseling Practices And Barriers, Leslie N. Durham, Leslie Durham

Dissertations and Theses (Open Access)

Chromosomal microarray (CMA) assesses chromosome copy number variants (CNVs) missed by standard karyotyping. The American College of Obstetricians and Gynecologists (ACOG) recommends CMA for all patients with fetuses with an ultrasound anomaly and suggests that it be made available to all women undergoing invasive testing. In order to assess prenatal genetic counselors’ (GCs) practices regarding the utilization of CMA we conducted a survey of their current practices, attitudes, and perceived barriers. Of the 192 respondents, 183 (95%) have incorporated CMA into clinical practice with the majority (64%) believing that the benefits of CMA outweigh the harms. However, only half (52%) …

Undergraduate Student Perceptions And Awareness Of Genetic Counseling, Amanda Gerard

Dissertations and Theses (Open Access)

Genetic counseling (GC) is a rapidly expanding field, and the supply of certified genetic counselors is currently unable to keep up with job demand. Research is fairly limited regarding the awareness and perceptions potential genetic counseling program applicants have of the field and what factors most influence their interest in the field. This study aimed to examine some of these topics. The current study includes data collected from 1,389 undergraduate students in the sciences at 23 universities across the United States who were surveyed regarding information related to their awareness, perceptions, knowledge, and interest in GC. Data analysis was performed …

Attitudes Of Clinicians To Wards Cardiac Surgery And Trisomy 18, Meagan Kaulfus

Dissertations and Theses (Open Access)

Trisomy 18 is an autosomal trisomy characterized by minor to major birth defects, severe disabilities, and high rates of pre- and neonatal mortality. Interventions for these infants have traditionally been withheld with focus instead on palliative support. The issues and attitudes surrounding surgical treatment of congenital heart defects, which occur in approximately 90% of infants with trisomy 18, is of our study’s interest as recent literature has indicated that cardiac surgery is being performed and may lead to improved survival compared to palliative care. In this study, the attitudes of clinicians of multiple specialties towards cardiac surgery for infants with …

Peptide Vaccine Formulation Controls The Duration Of Antigen Presentation And Magnitude Of Tumor‐Specific Cd8+ T Cell Response, Hiep Khong

Dissertations and Theses (Open Access)

Despite remarkable progresses in vaccinology, therapeutic cancer vaccines have not achieved their full potential. We previously showed that the duration of antigen presentation critically affected the quantity and quality of T cell response and subsequent anti‐tumor efficacy. Here we describe L‐tyrosine amino acid‐based microparticles as a novel peptide vaccine adjuvant for the induction of tumor‐specific T cells. L‐tyrosine microparticles did not induce inflammasome activation, but instead extended antigen presentation time. The consequent prolongation in antigen presentation translated into prolonged T cell proliferation and superior numbers and anti‐tumor function of vaccination‐induced CD8+ T cells. Indeed, prolonging antigen presentation by repeated injection …

Analysis Of The Biochemical And Cellular Activities Of Substrate Binding By The Molecular Chaperone Hsp110/Sse1, Veronica M. Garcia

Dissertations and Theses (Open Access)

Molecular chaperones ensure protein quality during protein synthesis, delivery, damage repair, and degradation. The ubiquitous and highly conserved molecular chaperone 70-kDa heat-shock proteins (Hsp70s) are essential in maintaining protein homeostasis by cycling through high and low affinity binding of unfolded protein clients to facilitate folding. The Hsp110 class of chaperones are divergent relatives of Hsp70 that are extremely effective in preventing protein aggregation but lack the hallmark folding activity seen in Hsp70s. Hsp110s serve as Hsp70 nucleotide exchange factors (NEF) that facilitate the Hsp70 folding cycle by inducing release of protein substrate from Hsp70, thus recycling the chaperone for a …

Characterization Of The Ubiquitin Ligase, Ube4b, In Endocytic Trafficking, Natalie Sirisaengtaksin, Natalie Sirisaengtaksin

Dissertations and Theses (Open Access)

Endocytosis is a process by which cells internalize membrane proteins to remove them from the plasma membrane, allowing cells to regulate the cell surface expression of transmembrane proteins. In this manner, cellular responses to extracellular cues may be tuned by limiting the number of proteins available at the cell surface. One particular class of proteins, receptor tyrosine kinases (RTK), is internalized upon binding to extracellular ligands during their residence at the cell surface. The epidermal growth factor receptor (EGFR) is an RTK whose trafficking through the endocytic pathway through the cell is well-documented. Stimulation of EGFR with its cognate ligand, …

The Role Of Adenosine Signaling In Mature Erythrocytes And Erythroid Progenitors, Hong Liu

Dissertations and Theses (Open Access)

Adenosine is a ubiquitous nucleoside in almost all the cells throughout our bodies. It is highly induced particularly under hypoxia or energy depletion conditions. Adenosine functions as a critical ligand, after binding to membrane-associated adenosine receptors, adenosine initiates a downstream signaling cascade and subsequently contributes to functions of nervous system, immune response, vascular function and even metabolism.

Hypoxia is a condition with limited O₂ availability in the whole body or a region of the body. It is a major consequence of many respiratory and cardiovascular diseases, as well as for people living and working at high altitudes or other …

Understanding The Mechanism Of Genomic Instability During Replicative Aging In Budding Yeast, Sangita Pal

Dissertations and Theses (Open Access)

Aging brings a gradual decline in molecular fidelity and biological functionality, resulting in age related phenotypes and diseases. Despite continued efforts to uncover the conserved aging pathways among eukaryotes, exact molecular causes of aging are still poorly understood. One of the most important hallmarks of aging is increased genomic instability. However, there remains much ambiguity as to the cause. I am studying the replicative life span (RLS) of the genetically tractable model organism Saccharomyces cerevisiae, or budding yeast using the innovative “mother enrichment program” as the method to isolate unparalleled numbers of aged yeast cells to investigate the molecular changes …

Targeting Autophagy To Improve Efficacy Of Cdk4/6 Inhibition In Breast Cancer, Smruthi Vijayaraghavan

Dissertations and Theses (Open Access)

Deregulation of the cell cycle machinery is a hallmark of cancer, leading to aberrant proliferation and tumorigenesis. The crucial role of the CDK4/6-Cyclin D pathway has led to the development and FDA approval (palbociclib, ribociclib) of CDK4/6 inhibitors for the treatment of advanced estrogen receptor positive breast cancer. However, three major clinical challenges remain: i) adverse events leading to discontinuation of therapy and ii) lack of reliable biomarkers to identify responsive patients and iii) acquired resistance to CDK4/6 inhibitors. Previous in vitro studies have shown that palbociclib mediated CDK4/6 inhibition induces G1 arrest and senescence in ER+ breast cancer cells, …

Stromal Fibroblasts Restrain The Rate Of Colon Cancer Progression And Metastasis By Suppressing Regulatory T Cells And Colon Cancer Stem Cells, Changsoo Kwak

Dissertations and Theses (Open Access)

The initiation, progression, and metastasis of tumors involve not only cancer cells, but also the tumor microenvironment, which consists of immune or inflammatory cells, fibroblasts, endothelial cells, and extracellular matrix components (ECM). Fibroblasts are ubiquitous stromal cells that can influence other neighboring cell types through the secretion of chemokines, cytokines, ECM, ECM remodeling enzymes, and other metabolites. Myofibroblasts are a distinct subtype of fibroblasts characterized by expression α-smooth muscle actin (αSMA). These cells are a dominant component of the microenvironment, and a FSP1 and FAP could be a different clone of fibroblasts. Myofibroblasts also have been known to contribute to …

Characterization Of The Role Of The Pkm101-Encoded T4ss Outer Membrane Core Complex In Substrate Transfer, Pilus Biogenesis, And Recipient Cell Contact, Jay E. Gordon

Dissertations and Theses (Open Access)

The bacterial type IV secretion systems (T4SS) encoded on the Escherichia coli pKM101 and R388 conjugative plasmids and the Agrobacterium tumefaciens virB operon are composed of 12 subunits arranged in an architecturally similar fashion. Structural studies of the T4SS from R388 (Trw_R388) highlighted the presence of a distinct outer membrane core complex (OMCC) and inner membrane complex (IMC) joined together by a central stalk. This thesis is focused on the development of the pKM101 model system and the role of an OMCC cap region formed by alpha helical antenna projections (AP) found in VirB10 and TraF_pKM101. …

Understanding Patient Safety Reports Via Multi-Label Text Classification And Semantic Representation, Chen Liang

Dissertations and Theses (Open Access)

Medical errors are the results of problems in health care delivery. One of the key steps to eliminate errors and improve patient safety is through patient safety event reporting. A patient safety report may record a number of critical factors that are involved in the health care when incidents, near misses, and unsafe conditions occur. Therefore, clinicians and risk management can generate actionable knowledge by harnessing useful information from reports. To date, efforts have been made to establish a nationwide reporting and error analysis mechanism. The increasing volume of reports has been driving improvement in quantity measures of patient safety. …

A Life Cycle Approach To The Development And Validation Of An Ontology Of The U.S. Common Rule (45 C.F.R. § 46), Francis Manion

Dissertations and Theses (Open Access)

Requirements for the protection of human research subjects stem from directly from federal regulation by the Department of Health and Human Services in Title 45 of the Code of Federal Regulations (C.F.R.) part 46. 15 other federal agencies include subpart A of part 46 verbatim in their own body of regulation. Hence 45 C.F.R. part 46 subpart A has come to be called colloquially the ‘Common Rule.’

Overall motivation for this study began as a desire to facilitate the ethical sharing of biospecimen samples from large biospecimen collections by using ontologies. Previous work demonstrated that in general the informed consent …

Targeting Apoptotic Pathways To Overcome Drug Resistance In Acute Myeloid Leukemia, Rongqing Pan

Dissertations and Theses (Open Access)

Evasion of apoptosis is integral to tumorigenesis and drug resistance. BCL-2 and p53 proteins represent two focal nodes in convergent apoptosis signaling. Upregulation of anti-apoptotic BCL-2 family members and inactivation of p53 functions are two canonical approaches exploited by cancer cells to escape apoptosis. In the current study, we find that BCL-2 protein is highly expressed in acute myeloid leukemia (AML) cells. BCL-2–specific inhibitor ABT-199 potently induces mitochondrial apoptosis in AML cells and effectively kills AML stem/progenitor cells. Our biomarker studies demonstrate that both BH3 profiling and the expression profiling of BCL-2 proteins may serve as predictive biomarkers for the …

Improving Syntactic Parsing Of Clinical Text Using Domain Knowledge, Min Jiang

Dissertations and Theses (Open Access)

Syntactic parsing is one of the fundamental tasks of Natural Language Processing (NLP). However, few studies have explored syntactic parsing in the medical domain. This dissertation systematically investigated different methods to improve the performance of syntactic parsing of clinical text, including (1) Constructing two clinical treebanks of discharge summaries and progress notes by developing annotation guidelines that handle missing elements in clinical sentences; (2) Retraining four state-of-the-art parsers, including the Stanford parser, Berkeley parser, Charniak parser, and Bikel parser, using clinical treebanks, and comparing their performance to identify better parsing approaches; and (3) Developing new methods to reduce syntactic ambiguity …

Regulation Of Hnrnpa1 By Micrornas Controls The Mir-18a–K-Ras Axis In Chemotherapy-Resistant Ovarian Cancer, Cristian Rodriguez-Aguayo, Paloma Del C Monroig, Roxana S Redis, Emine Bayraktar, Maria I Almeida, Cristina Ivan, Enrique Fuentes-Mattei, Mohammed H Rashed, Arturo Chavez-Reyes, Bulent Ozpolat, Rahul Mitra, Anil K Sood, George A Calin, Gabriel Lopez-Berestein

Faculty, Staff and Student Publications

The regulation of microRNA (miRNA) biogenesis, function and degradation involves a range of mechanisms, including interactions with RNA-binding proteins. The potential contribution of regulatory miRNAs to the expression of these RNA interactor proteins that could control other miRNAs expression is still unclear. Here we demonstrate a regulatory circuit involving oncogenic and tumor-suppressor miRNAs and an RNA-binding protein in a chemotherapy-resistant ovarian cancer model. We identified and characterized miR-15a-5p and miR-25-3p as negative regulators of hnRNPA1 expression, which is required for the processing of miR-18a-3p, an inhibitor of the

The Role Of Two Homologous E3 Ligases In Muscle Physiology, Gabrielle F. Gloston

Dissertations and Theses (Open Access)

Ubiquitin-mediated proteasomal degradation is an essential cellular function that is coordinated by three key components: E1 ubiquitin activating enzyme, E2 ubiquitin conjugating enzyme, and E3 ubiquitin ligases. There are an estimated 600 E3 ligases, some of which share high sequence homology; however, the functional significance often remains unknown. FBXL3 and FBXL21 are two homologous E3 ligases that have previously been reported to dictate circadian periodicity, with FBXL3 being the dominant E3 ligase and FBXL21 playing a regulatory role. A recent Yeast Two-Hybrid screen revealed a new shared target of FBXL3 and FBXL21: Telethonin (also known as TCAP). TCAP is a …