Medicine and Health Sciences Commons^™

Hypoxia Regulates Vessel-Modifying Macrophages And Vice Versa In Tumors, Kayla Jo Steinberger

Graduate Theses, Dissertations, and Problem Reports

Hypoxia, or low oxygen, is a common feature of solid tumors correlating with poor survival in cancer patients. Growing tumors need a blood supply to deliver oxygen. Tumors attempt to re-acquire oxygen by forming new blood vessels from nearby, pre-existing vessels, a process known as angiogenesis. Past treatments aimed at preventing this process yielded not only disappointing results in the clinic but sometimes worsened the patient’s prognosis making the tumor more hypoxic, emphasizing the urgent need for novel targets. In tumors, angiogenesis is notoriously dysfunctional resulting in leaky, under-perfused blood vessels which cannot adequately deliver oxygen and exacerbates hypoxia. Emerging …

Investigating The Effects Of Immune Checkpoint Inhibition And Combined Treatment With Evofosfamide On The Tumor Microenvironment Through Hypoxia Imaging, Kaytlyn Carter Mcneal

All ETDs from UAB

Colorectal cancer (CRC) is a prevalent and deadly cancer worldwide. While immunotherapy, particularly immune checkpoint inhibition, shows promise in various cancers, its efficacy in CRC and other tumor types is limited. Hypoxia, characterized by inadequate tissue oxygenation, critically drives cancer progression, promoting tumor growth, metastasis, chemotherapy resistance, and poor prognosis. Evofosfamide, a hypoxia-activating prodrug, is being evaluated in clinical trials for combined use with checkpoint blockade as a potential therapeutic strategy. This study investigates the impact of hypoxia on immune checkpoint inhibition, evofosfamide, and combination therapy, while utilizing non-invasive molecular imaging to develop analytical methods for quantifying and characterizing tumor …

The Role Of The Hypoxia-Inducible Factor 2 In Pancreatic Cancer: Mechanisms Of Tumor Immunosuppression And Intestinal Radioprotection, Carolina Garcia Garcia

Dissertations & Theses (Open Access)

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with dismal prognosis. The only curative option for patients is surgery, but over 80% of patients are not surgical candidates. Unfortunately, PDAC is resistant to the three remaining options. PDAC is characterized by a profoundly hypoxic and immunosuppressive stroma, which contributes to its therapeutic recalcitrance. Alpha-smooth muscle actin+ (αSMA+) cancer-associated fibroblasts (CAFs) are the most abundant stromal component, as well as mediators of stromal deposition. The hypoxia-inducible factors (HIF1 and HIF2) coordinate responses to hypoxia, yet, despite their known association to poor patient outcomes, their functions within the PDAC tumor microenvironment (TME) …

Targeting Metabolic Adaptations To Anti-Angiogenic Therapy In Ovarian Cancer, Deanna M. Glassman, Deanna Glassman

Dissertations & Theses (Open Access)

ABSTRACT

Background: Ovarian cancer is the most lethal gynecologic malignancy. Despite modest clinical improvements with anti-VEGF antibody (AVA) therapy, adaptive resistance is nearly ubiquitous and additional therapeutic options are limited. A dependence on glutamine metabolism, via the enzyme glutaminase (GLS), is a known mechanism of adaptive resistance.

Purpose: To assess the efficacy of a glutaminase inhibitor as a means of exploiting the metabolic vulnerability of glutamine dependence that develops as a result of adaptive resistance to AVA therapy.

Experimental Design: We used a glutaminase inhibitor (GLSi) synthesized at MD Anderson Cancer Center for all in vitro and in vivo experiments. …

Severe Hypoxia Up-Regulates Gluconeogenesis In Daphnia, Morad C. Malek

Undergraduate Honors Theses

Hypoxia is a significant low oxygen state that has complex and diverse impacts on organisms. In aerobes, various adaptive responses to hypoxia are observed that vary depending on the level of oxygen depletion and previous adaptation, hence the continued attention to hypoxia as an important abiotic stressor. Adaptive responses to hypoxia are primarily governed by the hypoxia-inducible factors (HIFs), which activate downstream genetic pathways responsible for oxygen transport and metabolic plasticity. In aquatic habitats, oxygen availability can vary greatly over time and space. Therefore, aquatic organisms’ adaptation to hypoxia is likely pervasive, especially in genotypes originating from waterbodies prone to …

Investigating The Effects Of In-Vivo Therapeutics Hypoxia Treatment Paradigms In Neurite Outgrowth Patterns, Jae Hyun Yoo

Theses and Dissertations--Medical Sciences

Spinal cord injury, specifically in the cervical C3-C4 region of the cervical spine, contributes to impaired breathing and a diminished quality of life. Therefore it is important to find effective and safe therapeutics to restore breathing function. Indeed, there are a myriad of research being performed in addition to valuable collaboration amongst different institutions. As such, inspired by a previous experiment, we decided to test our hypothesis that an enriching environment consisting of different hypoxic environments - sustained and intermittent hypoxia alongside normoxia - would result in neurite outgrowth. Moreover, we hypothesized that sustained hypoxia would result in the greatest …

Exosomes Secreted Under Hypoxia Enhance Stemness In Ewing’S Sarcoma And Transform Microenvironment Cells, Matthew J. Kling

Theses & Dissertations

Intercellular communication between tumor cells and stroma within the hypoxic microenvironment promote aggressiveness and poor patient prognoses in ways that remain unclear. Here we show that hypoxic Ewing’s sarcoma (EWS) cells release exosomes that promote sphere formation, a stem-like phenotype, in EWS cells by enhancing survival and a cancer-associated phenotype in fibroblasts (CAFs). Given that hypoxia enriches for stem-like cells, we exposed EWS cells to hypoxia and hypoxic EWS-derived exosomes and assessed the stem cell phenotype. Hypoxia and hypoxic EWS-derived exosomewere found to enhance TIC formation in vitro and in vivo by reprogramming EWS cells. Analysis of the hypoxic exosomal …

Kinetic Analysis Of Dynamic Pet For Molecular, Functional And Physiological Characterization Of Diseases, Fiona Li

Electronic Thesis and Dissertation Repository

PET with targeted probes may better elucidate the molecular and functional basis of diseases. The widely used standardized uptake value from static imaging, however, cannot quantify the probe uptake processes like perfusion, permeability, binding to and disassociation (k₄) from target. The overarching thesis goal is to develop a model to enable kinetic analysis of dynamic imaging to separate these processes.

As perfusion delivery is not modelled in the current standard two tissue compartment (S2TC) model, I developed a flow modified two tissue compartment (F2TC) model that incorporates the blood flow effect. The model’s performances were investigated with simulation. …

The Effect Of Hypoxia On Brain Cell Proliferation In Weakly Electric Fish, Petrocephalus Degeni, Kaitlin Klovdahl

Senior Theses and Projects

Oxygen levels tend to remain at a steady state concentration in the Earth’s atmosphere, yet in some bodies of water, they can fluctuate and decrease drastically. Many organisms that inhabit the swamps, lakes, streams, and parts of the ocean where this occurs have evolved adaptations to manage this environmental uncertainty and continue normal oxygen consumption. The Lwamunda swamp in Uganda is chronically hypoxic, yet it is home to many species, including the electric fish Petrocephalus degeni. P. degeni are unusual by nature of their immense brain, and the Lwamunda swamp appears ill-suited for maintaining this large, metabolically active organ. To …

Elucidating The Role Of Hedgehog Signaling In Tumor Cell Response To Dna Damage And Microenvironmental Stress, Tshering Dolma Lama-Sherpa

All ETDs from UAB

Hypoxia within solid tumors presents as a barrier to the effectiveness of cancer treatment. Hypoxia has been implicated in cancer cell resistance to standard therapies used in the clinic to treat breast cancer. Additionally, the treatment resistance mechanisms in cancer cells are exacerbated by oncogenic pathways that enable adaptation to the hypoxia and facilitate therapy resistance. Cancer cells often co-opt signaling pathways essential for embryonic development as a defense against cellular attacks. Hedgehog (Hh) signaling pathway is one of such embryonic development pathways that have been implicated in mitigating cancer growth, metastasis, and resistance to therapy. Hh signaling pathway promotes …

Translational Control Of Stress Induced Breast Cancer Plasticity, Michael Jewer

Electronic Thesis and Dissertation Repository

Cancer cell plasticity, whereby stem-cell-like properties are acquired in response to stress, represents a major challenge in cancer treatment. Using cell line and patient-derived xenograft (PDX) models, we demonstrate that translational reprogramming occurs in response to stresses such as hypoxia and chemotherapy which elicits stem cell properties in breast cancer. Other stresses like chemotherapy demonstrate the translational inhibition that has been well characterized as an integral hypoxic cellular response. The inhibition of translation is primarily regulated at initiation by mTOR/4E-BP1 and PERK/eIF2α signalling. We identify previously undescribed 5’ untranslated regions (5’UTRs) of plasticity-associated genes like NANOG, SNAIL and NODAL. …

The Role Of The St6gal-I Sialyltrasferase In Protecting Tumor Cells From Hypoxic Stress, Robert Brent Jones

All ETDs from UAB

An emerging concept in cancer biology is that surface glycosylation can play important roles in the regulation of cancer development and progression. Our group and others have shown that ST6Gal-I, a sialyltransferase that adds α2-6-linked sialic acids to N-glycosylated proteins, is upregulated in many cancers. Furthermore, data has indicated that ST6Gal-I acts as a pro-survival factor in a variety of settings, including resistance to chemotherapeutic drugs, radiotherapy resistance, and serum deprivation. The work presented in this dissertation adds to this understanding of ST6Gal-I’s role as a potent pro-survival factor and explores ST6Gal-I’s function in aiding tumor cells to survive hypoxic …

Validation Of A Hyperspectral Nirs Method For Measuring Tissue Oxygen Saturation, Matthew Kewin

Electronic Thesis and Dissertation Repository

Brain injury during preterm infancy can cause serious intellectual and behavioral disabilities, as such, measurements of cerebral health are needed to aid in the diagnosis and treatment of these injuries. Near infrared spectroscopy (NIRS) is considered ideal for this purpose because it is non-invasive and provides a continuous measure of tissue oxygen saturation (StO₂), a key marker of cerebral health. Current commercial NIRS systems have considerable variability between devices and between infants restricting them to monitoring trends. Time-resolved (TR) NIRS is considered the gold standard in biomedical optics for quantifying tissue optical properties, but the technology is more …

Neuroprotective Functions Of Docosahexaenoic Acid And Epidermal Fatty Acid Binding Protein, Manuel Luis Montero

Loma Linda University Electronic Theses, Dissertations & Projects

Lipotoxicity (LTx) is involved in mostly every process of neuronal injury. Using NGFDPC12 cells we show that palmitic acid (PA) induces the expression of stress response genes HIF-1α and BNIP3, increases the accumulation of reactive oxygen species, and decreases cell viability by apoptosis. Inhibition of cathepsins does not rescue neurons from PA-LTx but inhibition of necroptosis and promotion of autophagy do. DHA decreases the expression of HIF-1α and BNIP3 and rescues PA-induced cell death by inhibiting apoptosis and necroptosis. Besides DHA stimulates the mRNA expression, phosphorylation and conjugation of autophagy controlling proteins. Inhibiting autophagy during DHA treatment decreases its capacity …

Effect Of Exercise And Hypoxia On Plasma Telomerase, Charli D. Aguilar

UNLV Theses, Dissertations, Professional Papers, and Capstones

Introduction: Telomerase reverse transcriptase (TERT) is the enzyme that adds telomeric sequences to the end of linear chromosomes. Exercise has shown to upregulate acutely leukocyte TERT after just 30 minutes of running on a treadmill at 80% of VO2max (Denham et al., 2016). Hypoxia inducible factor 1 (HIF-1) is also a mediator of TERT in in vitro (Nishi et al., 2004). Moderate acute exposure to hypoxia was associated with substantial increases in plasma TERT in a recent study on rats (Wang et al., 2014). The specific aim of the current study was to identify if acute hypoxia upregulates plasma TERT …

Metabolic And Expression Changes Associated With A Mouse Model Of Intrauterine Growth Restriction (Iugr), Bethany N. Radford

Electronic Thesis and Dissertation Repository

Intrauterine growth restriction (IUGR) is a pregnancy condition where fetal growth is suboptimal, resulting in an infant born small for gestational age (<10th percentile) and is associated with metabolic disorders such as type 2 diabetes in adulthood. This study aims to understand tissue-specific adaptations to fetal undernutrition which predispose the individual to metabolic disorders in adulthood. A model of growth restriction in mice was established using 70% of maternal ad libitum total food (g) (E6.5-birth). At weaning, male offspring received standard chow or a HFHS diet. Body weight and random blood glucose levels were measured at 6 months. To assess metabolism at 6 or 7 months, glucose tolerance, pyruvate challenge and hepatic portal vein insulin challenge tests were administered and serum peptide markers for obesity and diabetes were measured. Metabolic cages were also used at 2 and 7 months to measure activity, food intake and respiratory exchange ratios (RERs). Adult liver, adipose and skeletal muscle and fetal liver was collected for RNA sequencing. Maternal nutrient restricted (MNR) offspring were growth restricted with disproportionately smaller fetal livers. 19% of standard chow-fed MNR offspring became glucose intolerant. On an isocaloric high-fat high-sugar diet no differences in MNR growth or glucose metabolism were detected. However, RERs were reduced at all timepoints in MNR on a HFHS relative to MNR on standard chow. Differences in transcription of genes involved in hypoxia signalling were detected and HIF-2a and HIF-3a proteins were increased in fetal liver of MNR offspring. Genes differentially expressed in the fetus were not differentially expressed at 6 months. Gene expression of metabolically regulatory transcripts in liver, adipose and skeletal muscle did not differ in all MNR and glucose intolerant MNR relative to controls. This model results in a susceptible and non-susceptible population of maternal nutrient restricted offspring and supports the concept of hypoxia signalling contributing to fetal adaptations. Understanding adaptations in hepatic hypoxia signalling in response to fetal undernutrition and how they vary in susceptible and unsusceptible populations will provide insight into how fetal nutrition can influence adult metabolism.

Priming Cardiovascular Stem Cells For Transplantation Using Short-Term Hypoxia, Ivan Hernandez

Electronic Theses, Projects, and Dissertations

Conventional medical treatments fail to address the underlying problems associated with the damage inflicted by a coronary event. Thus, the long-term prognosis of patients admitted for heart failure is disheartening, with reported survival rates of 25 percent. Recent advances in stem cell research highlight the potential benefits of autologous stem cell transplantation for stimulating repair in heart tissue. However, a majority of those suffering from cardiovascular diseases are older adults whose autologous cells no longer possess optimum functional capacity. Additional work is needed to identify the optimal cell types or conditions that will promote cardiovascular regeneration across all age groups. …

Identification Of Novel Hif1a Target Genes That Regulate Tumor Progression And Metastasis, Danielle L. Peacock

Theses and Dissertations (ETD)

Hypoxia is a hallmark of most solid tumors. In response to hypoxic stress tumor cells adapt by regulating survival, metabolism and angiogenesis. The heterodimeric HypoxiaInducible Factor (HIF) transcription factors are the master regulators of this response. HIFs play key roles in many critical aspects of cancer biology including angiogenesis, stem cell maintenance, metabolic reprogramming, invasion, metastasis and resistance to radiation therapy and chemotherapy. Overexpression of HIF-1α and HIF-2α has been documented in multiple human cancers and HIF-1 protein is over-expressed in ~30% of primary breast tumors and ~70% of metastases, which independently correlates with poor prognosis and decreased survival in …

Vegf And Sympathetic Perivascular Nerves Contribute To Hypoxic Remodeling Of Ovine Cranial Arteries, Olayemi Olufikayo Adeoye

Loma Linda University Electronic Theses, Dissertations & Projects

Chronic hypoxia complicates many pregnancies and can result in postnatal pathologies that include compromised fetal cardiovascular structure and function. Mechanisms involved remain unclear. Because hypoxia increases production of VEGF, known to modulate smooth muscle (SM) phenotype, this thesis explored the hypothesis that VEGF contributes to hypoxic fetal vascular remodeling through direct effects on SM cells and indirectly through perivascular nerves. Using a chronic hypoxia sheep model, this work demonstrated that: 1) hypoxia potently upregulates VEGF receptor expression but not endogenous VEGF level in fetal ovine carotid arteries; 2) both chronic hypoxia and VEGF exert similar effects on smooth muscle contractile …

Roles Of Pgc-1Α/Ppars Pathway In Regulating Insulin Sensitivity In Mouse Skeletal Muscle Cells Under Prolonged Hypoxia, Yunyan Zhang

Electronic Thesis and Dissertation Repository

Using the C₂C₁₂ mouse myoblast cell line, I investigated how prolonged hypoxia affected components of the insulin signalling and FAO/PGC-1α/PPARs pathways, as they might impact insulin sensitivity in skeletal muscle cells.

Hypoxia resulted in lower p-Akt (Thr 308) and higher total cellular GLUT4 protein levels after 7 days of differentiation. This coincided with higher triglyceride content and alterations of the FAO/PGC-1α/PPARs components, both of which could contribute to the changes observed in the components of the insulin signalling pathway. Specifically, cells differentiating in 1% O₂ had lower SIRT1, PPAR- α, FATP4 and MCAD mRNA; accompanied by …

Contribution Of The Unfolded Protein Response To Vegf Expression, Ethel Rose Pereira

Theses and Dissertations (ETD)

Tumor cells experience a limiting microenvironment due to inadequate vascularization that can affect the normal functioning of intracellular organelles. In the case of the endoplasmic reticulum, the limiting environment is further exacerbated by the high metabolic demands of the tumor cells, which together interfere with the proper maturation of nascent proteins synthesized there. The resultant accumulation of unfolded proteins activates a signal transduction pathway known as the Unfolded Protein Response, which serves primarily to protect the cell during stress and helps restore homeostasis to this organelle. As tumors expand resulting in regions that are a greater distance from functional blood …

The Effects Of Oxygen On The Electrophysiology Of Co2/H+-Chemosensitive And -Insensitive Neurons Of The Solitary Complex Of The Rat, Michael Patrick Matott

USF Tampa Graduate Theses and Dissertations

This study tested the hypothesis that decreasing the control O₂ level from 95% to 40% (5% CO₂ + 55% N₂) maintains viability in caudal solitary complex (cSC) neurons in transverse slices (~300-400ꝳ) prepared from neonatal rat (P2-22) maintained at 32-34°C. The underlying rationale is to reduce exposure to redox and nitrosative stimuli generated during several hours of exposure to 95% O₂ that produces a tissue O₂ tension throughout the slice which is in excess of 203 kPa (2.0 atmospheres absolute,ATA) oxygen. Whole cell recordings of cSC neurons maintained in 40% O₂ exhibited spontaneous …

The Vascular Link Between Intrauterine Hypoxia And Postnatal Cardiovascular Pathology, Jennifer A. Thompson

Electronic Thesis and Dissertation Repository

The effect of intrauterine hypoxia on arterial development was evaluated with use of large and small animal models. Analyses included expression and deposition of extracellular matrix (ECM) proteins, differentiation and proliferation of vascular smooth muscle cells (VSMCs), intima formation and wall thickening. A comprehensive investigation of possible molecular, mechanical and hormonal mediators of altered arterial development was afforded by a sheep model with both acute and chronic hypoxemia studies, whereas a guinea pig model allowed for long-term study. Our findings show that chronically hypoxic fetal sheep and intrauterine growth restricted (IUGR) guinea pigs exhibit a reduction in elastic fibre content …

Assessment Of Mitochondrial Stressors On Cellular Bioenergetics, Blake Reid Zelickson

All ETDs from UAB

The mitochondrion plays a central role in the maintenance of bioenergetic function through the production of ATP and essential metabolites. The development of mitochondrial bioenergetic defects is a hallmark of important pathologies such as cardiovascular and liver diseases. It is well established that a decrease in mitochondrial function, typically of 20-40%, is associated with the progression of these pathologies. Causal relationships have been more difficult to establish because of the challenge of assessing mitochondrial function in a cellular setting. Specifically, it is known that mitochondria function at less than their maximal respiratory capacity and the remainder, known as reserve or …

Secreted Factors From Human Umbilical Cord Blood Cells Protect Oligodendrocytes From Ischemic Insult, Derrick Rowe

USF Tampa Graduate Theses and Dissertations

Oligodendrocytes (OL)s are the dominant cell type in the white matter and are integral for synaptic transmission essential for proper neuronal communication between brain areas. Previous studies have shown that intravenous administration of the mononuclear fraction of human umbilical cord blood (HUCB) cells in rat models of stroke reduced white matter injury, gray matter injury and behavioral deficits. Yet the mechanisms used by HUCB cells remain unknown in ischemic injury. These studies will investigate both in vitro and in vivo approaches to elucidate this mechanism in OLs. When mature primary OLs were coincubated with HUCB cells, HUCB cells secreted soluble …

Long-Term Hypoxia Regulates Cortisol Biosynthesis In The Ovine Fetal Adrenal Cortex, Vladimir Enrique Vargas

Loma Linda University Electronic Theses, Dissertations & Projects

Previous studies demonstrated enhanced fetal adrenal cortisol biosynthesis following exposure to long-term hypoxia (LTH). The studies presented here were designed to determine the mechanism(s) regulating this important adaptive endocrine response. Ewes were maintained at high altitude (3,820 m) from approximately day 40 to 138-141 of gestation. Fetal adrenal glands were then collected from LTH and age matched normoxic controls. Dispersed fetal adrenal cortical cells (FACs) were untreated, treated with ACTH, treated in combination with ACTH precursors (POMC and 22-kDa pro-ACTH), or pre-treated with H-89 and or UO126 followed by ACTH treatment. Following ACTH treatment, cortisol biosynthesis increased in both groups …

The Role Of Extracellular Matrix And Matrix-Degrading Proteases In Neonatal Hypoxic-Ischemic Injury, Christopher C. Leonardo

USF Tampa Graduate Theses and Dissertations

Improvements in medical care over recent decades have increased the number of premature and low birth weight infants that survive hypoxic-ischemic (H-I) insults. Because there is a rising incidence in diseases associated with these events, it is critical to develop effective therapies to treat the various resulting neuropathies. Extracellular matrix constitutes the majority of brain parenchyma. Lecticans and matrix-degrading proteases including ADAMTSs (a disintegrin and metalloproteinase with thrombospondin repeats) and matrix metalloproteinases (MMPs) exert effects on cell viability and may be associated with either protective or destructive processes after H-I. Both ADAMTSs (Cross et al. 2006; Tian et al. 2007) …

Post-Juvenile Brain Development Modulates Seizure Characteristics And Diazepam Efficacy In The Rat Pilocarpine-Se Model, William H. Holbert Ii

Theses and Dissertations

These studies were completed to examine how status epilpeticus seizure characteristics are modulated during post-juvenile brain development. This may determine if postnatal age in rats is a better identifier of stages of post-juvenile brain development. The first study fully detailed the acute discrete seizure phase of the rat pilocarpine-SE model. Results for this study showed that Racine behavioral severity score, spike frequency, and seizure severity during the acute discrete seizure phase change in relation to post-juvenile brain developmental stages. The second study fully detailed early and late patterns of status epilepticus. Results for this study displayed modulation of time in …