Pharmacology, Toxicology and Environmental Health Commons^™

Dual Inhibition Of The Pi3k/Akt And Mek5/Erk5 Pathways For The Treatment Of Breast Cancer, Thomas Douglas Wright

Electronic Theses and Dissertations

Breast cancer is a heterogeneous disease state with several challenging frontiers. In particular, aberrations in the Phosphoinositide-3-kinase (PI3K) and Mitogen Activated Protein Kinase (MAPK) pathways have been linked to increased breast cancer proliferation and survival. It has been proposed that these survival characteristics are enhanced through compensatory signaling and crosstalk mechanisms. New evidence suggests that MEK5/ERK5, a member of the MAPK family, is a crucial component in the proliferation and survival of several aggressive cancers. We hypothesize that inhibiting both PI3K/Akt and MEK5/ERK5 pathways will decrease cell viability while maintaining limited collateral toxicity. In this study, we examined the effects …

Development Of A Lectin-Fc Fusion Protein With Antiviral And Anti-Cancer Activity., Matthew William Dent

Electronic Theses and Dissertations

This thesis describes the development of a novel lectin-Fc fusion protein and its antiviral and anti-cancer activity. The molecule, Avaren-Fc (AvFc), is a fusion of a variant of the actinomycete lectin actinohivin (Avaren) and the Fc region of human IgG1, and is selective for the terminal α1,2-mannose residues found at the ends of high-mannose-type glycans that can be found on the surface of certain heavily glycosylated viruses and cancer cells. Here, AvFc was found to be able to neutralize simian immunodeficiency virus as well as Hepatitis C virus with nanomolar IC₅₀ values. Furthermore, AvFc recognizes a number of cell …

Paraoxonase 2 Is Critical For Non-Small Cell Lung Carcinoma Proliferation., Aaron Whitt

Electronic Theses and Dissertations

Non-small cell lung carcinoma (NSCLC) comprises 85% of lung cancer diagnoses and is plagued by drug resistance. Thus, elucidating the underlying mechanisms of NSCLC is paramount to expand future treatment options. Paraoxonase 2 (PON2), an intracellular enzyme with arylesterase and lactonase functions, has well-established anti-atherosclerotic activity. Recent studies show PON2 is overexpressed in a variety of tumors and confers drug resistance, although these interactions have not been thoroughly examined in NSCLC. Thus, we sought to investigate the role of PON2 in cellular proliferation using PON2-knockout mice, primary mouse cells, and NSCLC cell lines. Using these approaches, we demonstrate that PON2 …

Development Of Bar-Peptide Nanoparticles And Electrospun Fibers For The Prevention And Treatment Of Oral Biofilms., Mohamed Yehia Mahmoud

Electronic Theses and Dissertations

Background: Periodontal diseases are globally prevalent inflammatory disorders that affect ~47% of U.S adults. Porphyromonas gingivalis (Pg) has been identified as a “keystone” pathogen that disrupts host-microbe homeostasis and contributes to the initiation and progression of periodontitis. Pg associates with oral streptococci in supragingival plaque and this interaction represents a potential target for therapeutic intervention. Previously our group developed a peptide (designated BAR), that potently inhibits Pg/Streptococcus gordonii (Sg) adherence in vitro and Pg virulence in a murine model of periodontitis. While efficacious, BAR (SspB Adherence Region) provided transient inhibition and required higher concentrations of BAR to disrupt established …

A Mechanistic Study Of The Teratogenic Potential Of 4-O-Methylhonokiol (Mh) On Japanese Medaka (Oryzias Latipes), Santu Kumar Singha

Electronic Theses and Dissertations

An additional goal of this project was to characterize the Wnt/β-catenin signaling pathway to unravel the adverse potential of MH on the cardiovascular system (CVS). Our study suggested that MH-mediated cardiovascular injury may be caused due to upregulation of some major components of the Wnt/β-catenin pathway through expression of excessive pro-inflammatory mediators. Moreover MH decreased expression of ErbB3 and NRG-2 suggesting impaired cardiac structure. MH exposure caused a slow heartbeat blood occlusion absence of blood circulation decreased hatching efficiency and increased mortality in medaka embryos in a concentration- and time-dependent manner. MH might cause blood vessel occlusion by increasing the …

Safety Assessment And Chemical Fingerprint Analysis Of Medicinal Plants Commonly Consumed As Herbal Teas; Rooibos (Aspalathus Linearis) And Moringa (Moringa Oleifera), Omer I. Fantoukh

Electronic Theses and Dissertations

The first chapter discusses the significance of natural products, safety challenges, and quality issues concisely. Specifically, the impact of herb-drug interaction on consumers and the quest for chemical markers for chemical fingerprinting development are provided. Rooibos tea (Aspalathus linearis) is a popular South African herbal tea enjoyed worldwide. Limited reports indicate the potential of rooibos tea to alter the activity of CYP450 isozymes. In chapter two, the phytochemical investigation of A. linearis resulted in the isolation and characterization of 14 phenolic compounds. Safety assessment of the phytochemicals through interaction with CYP, PXR, and P gp was conducted. The …

Continuous Production Of Raloxifene Hydrochloride Loaded Nanostructured Lipid Carriers Using Hot-Melt Extrusion Technology, Derick Muhindo

Electronic Theses and Dissertations

The aim of this study was to utilize a continuous process for the production of Raloxifene Hydrochloride (RX-HCl) loaded NLC formulations for extended drug release using hot-melt extrusion technology coupled with probe sonication, and also to evaluate the in vitro characteristics of the prepared NLCs by particle size, PDI, zeta potential, entrapment efficiency, drug loading, and in vitro drug release profile. Preparation of the NLCs using HME technology involved two main steps, first formation of a pre-emulsion after extrusion and then size reduction of the pre-emulsion using probe sonication to obtain the NLCs. Process parameters for the extrusion process like …

Developing Zebrafish As An In Vivo Model To Screen Compounds For Anti-Cancer Activity In Human Breast Cancer, Trisha Dhawan

Electronic Theses and Dissertations

Breast Cancer (BC) is the most frequently diagnosed cancer; 1:8 women are at risk of developing BC in her lifetime. Cancer metastasis causes the majority of deaths in BC patients. Moreover, side effects of traditional chemotherapeutic drugs (TCD) impair the quality of life of these patients. Discovery and development of safe and effective new therapies is imperative for the treatment of BC and targeting metastasis. The goal herein is to further expand the applicability of in vivo xenotransplantation of human BC cells in transgenic zebrafish to screen potential chemotherapeutics for toxicity and efficacy. For xenotransplantation, MCF-7, BT-474, and MDA-MB-231 BC …

The Independent And Combined Effects Of Hypoxia And Tributyltin On The Eastern Oyster, Crassostrea Virginica, Ann Fairly Barnett

Electronic Theses and Dissertations

Oysters are vital to the health of estuarine ecosystems and provide critical ecosystem services, such as water quality improvement, nursery habitat for commercially important fisheries, and shoreline stabilization. Despite their ecological and economic importance, oyster reefs are exposed to many stressors, and oyster populations in Mississippi have declined dramatically in recent years. The present study focuses on the effects of hypoxia and tributyltin (TBT) on the Eastern oyster, Crassostrea virginica. Hypoxic events are increasingly comin coastal ecosystems worldwide, and TBT is a legacy toxicant once used as an antifoulant. The effects of these stressors were assessed on adult oysters deployed …

Implementing Mass Spectrometry For The Structural And Compositional Analysis Of Proteins, Mohammad Riaz

Electronic Theses and Dissertations

Lectins are sugar-binding proteins that perform various biological functions such as cellular recognition attachments etc. Pulses the dried edible seeds of certain plants are great sources of lectins and a proteomics approach directed at lectins identification would bring substantial improvement in the lectin identification process. Lectins from nine different plant species were analyzed through SDS-PAGE and proteomics analysis. After LC-MS/MS analysis proteins were identified with protein database searches using Uniprot. Functionally uncharacterized proteins were identified with database searches were annotated with the Pfam and NCBI-CCD databases. In-vitro pharmacological screening will be carried out to assess the pharmacological effects of these …

Pharmacokinetic Study Of Novel Anthraquinone Analogues, Yuhan Guo

Electronic Theses and Dissertations

Small molecules functioning as negative regulators of MDM2 have been considered as promising anti-cancer agents. A series of novel anthraquinone (AQ) analogues upregulate p53, a well-known tumor suppressor, by inactivating its antagonist protein MDM2. The novel AQ compounds synthesized through the modifications on the rhein scaffold were reported to have successfully arrested tumor growth. To have a better understanding of their underlying metabolism in vivo, pharmacokinetic (PK) studies were performed for the AQ compounds. A selective, accurate and reproducible assay methodology for PK study was set up for each AQ compound. The stabilities of AQ compounds were then evaluated …

Pyrrolo[2,3-D]Pyrimidine Classical Antifolates For Targeted Cancer Chemotherapy- Applications Of Bioisosteric And Regioisomeric Substitutions For Improved Tumor-Selectivity And Potency, Manasa Punaha Ravindra

Electronic Theses and Dissertations

In 2018, it is estimated that 1,735,350 new cases of cancer and 609,640 deaths from the disease will be diagnosed in the United States alone. Conventional chemotherapy is by far the most successful category of clinical oncology, having cured (complete remission (CR), without return) or provided clinical benefit to millions of people. However, since its earliest discovery, the major causes of failure of conventional cancer chemotherapy have been dose-limiting toxicities and development of resistance. There is a desperate ongoing search for new cancer therapies as tumor-targeted agents (without harming normal cells or tissues) with low propensity for the development of …

Epidermal Growth Factor-Like Ligands Regulate Dimer Selection., Jamie S. Rush

Electronic Theses and Dissertations

There are thirteen known endogenous EGF-like ligands. We previously reported that Betacellulin (BTC) increases ligand-mediated corneal wound healing more than Epidermal Growth Factor (EGF) [Peterson et al. (2014) IOVS 55(5):2870-80], although the molecular reason for this is unknown. Despite being better at promoting wound healing via enhanced cell migration, BTC has reduced receptor affinity and weaker induction of EGFR phosphorylation. These data indicate that BTC’s response is not due to enhanced affinity or EGFR-kinase activity. Receptor phosphorylation and proximity ligation assays indicate that BTC treatment significantly increases ErbB3 phosphorylation and EGFR:ErbB3 heterodimers. BTC traffics EGFR at a faster rate than …

Particulate Hexavalent Chromium Does Not Induce Centrosome Amplification In Sperm Whale And Bowhead Whale Cells., Jennifer Haruka Toyoda

Electronic Theses and Dissertations

Hexavalent chromium [Cr(VI)] is a widespread environmental and occupational carcinogen. The mechanism of carcinogenesis remains poorly understood, but chromosome instability (CIN) is the dominant theory. How numerical CIN arises is unclear, but it correlates with centrosome amplification. Both phenotypes are hallmarks of cancers, early events in carcinogenesis, and have been shown to occur after Cr(VI) exposure to human skin and lung fibroblasts. In this study, we investigate numerical CIN and centrosome amplification in whale cells. Whales are our closest marine relatives, have long lifespans, and are exposed to environmental Cr(VI). Importantly, they have low cancer rates and cell culture studies …

The Role Of Cyp2a5 In Cadmium-Induced Liver Injury, Julia Salamat

Electronic Theses and Dissertations

Cadmium is present in food and groundwater. Tobacco smoking and occupational exposure are also major sources for cadmium. Cadmium is primarily accumulated in liver, a major organ metabolizing exogenous chemicals. Chemical metabolism may cause detoxification, but it can also cause bio-activation resulting in liver damage. Cytochrome P450s (CYP) are major liver metabolism enzymes, and cadmium chloride (CdCl2) can induce CYP2A5 in mice. We examined the effect of CYP2A5 on CdCl2-induced liver injury using CYP2A5-knockout (cyp2a5-/-) mice. The cyp2a5-/- mice and their control WT mice were injected CdCl2 intraperitoneally at 5 mg/kg body weight, respectively, to induce liver injury. …

The Role Of Cathelicidin In The Regulation Of Gut Microbiota And Inflammasome Activation In Alcoholic Liver Disease., Fengyuan Li

Electronic Theses and Dissertations

Alcoholic liver disease (ALD) is characterized by gut dysbiosis and hepatic and intestinal inflammation. Gut microbiota is critically maintained by antimicrobial peptides (AMPs) expressed in the epithelial and immune cells. AMPs are also identified as immune-regulators in various diseases. Previous studies demonstrated that deficiency of AMPs REG3 lectins exacerbated alcoholic steatohepatitis. LL-37 is the sole member of human cathelicidin AMP family, named CRAMP in mouse. Despite of the extensive studies in infectious diseases and in gut-microbiota-related inflammatory bowel disease, the role of LL-37/CRAMP in ALD is yet unknown. Our previous studies showed a decreased intestinal CRAMP in a mouse model …

Egfr Signaling From The Early Endosome., Julie A. Gosney

Electronic Theses and Dissertations

The epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase that is an integral component of proliferative signaling. When activated by a ligand at the plasma membrane, EGFR dimerizes with another ErbB family receptor, leading to kinase domain activation and transphosphorylation of C-terminus tyrosine residues. These phosphotyrosines act as crucial regulators of EGFR signaling as effector proteins dock to the receptor at these sites. The receptor undergoes clathrin-mediated endocytosis into early endosomes, where it can then be trafficked to a lysosome for degradation. However, the kinase domain of EGFR retains its activity during trafficking, suggesting that EGFR can continue …

Wnt/Β-Catenin Mediated Cancer Stem Cell Activation In Hepatocellular Carcinoma., Harshulkumar M. Pandit

Electronic Theses and Dissertations

Hepatocellular carcinoma (HCC) is one of the deadliest cancers, with variable presentation, high chemotherapy resistance and early tumor recurrence. In this dissertation, we have systematically enriched, identified and characterized HCC cancer stem cells (CSCs) from 3 different HCC cell lines (Hepa1-6, HepG2, and Hep3B) using in vitro serum-free culture method. Enriched spheroids acquired CSC properties, primarily self-renewal capability, spheroid formation ability, and drug resistance. Heterogeneous CSCs enriched from Hepa1-6 cells demonstrated higher tumor initiation and proliferation capability in vivo, compared to control HCC cells in orthotopic immunocompetent mouse model. EpCAM+ CSCs were significantly enriched within heterogeneous Hepa1-6 CSC spheroids. Consequently, …

A Novel Fibroblast Growth Factor 1 Variant Reverses Nonalcoholic Fatty Liver Disease In Type 2 Diabetes., Qian Lin

Electronic Theses and Dissertations

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disorder and is strongly associated with type 2 diabetes (T2D). Our recently engineered FGF1 partial agonist, carrying triple mutations (FGF1^△HBS) exhibits greatly reduced proliferative potential, while preserving the full metabolic activity of wild-type FGF1. This study tests the preventive and therapeutic effects of FGF1^△HBS on NAFLD in db/db T2D and explores potential mechanisms. The results showed that administration of FGF1^△HBS to 2-month-old db/db mice for 2 months constantly lowered blood glucose levels, improved insulin sensitivity, and lowered liver weight, lipid deposition, and …

Deciphering The Role Of Human Arylamine N-Acetyltransferase 1 (Nat1) In Breast Cancer Cell Metabolism Using A Systems Biology Approach., Samantha Marie Carlisle

Electronic Theses and Dissertations

Background: Human arylamine N-acetyltransferase 1 (NAT1) is a phase II xenobiotic metabolizing enzyme found in almost all tissues. NAT1 can additionally hydrolyze acetyl-coenzyme A (acetyl-CoA) in the absence of an arylamine substrate. NAT1 expression varies inter-individually and is elevated in several cancers including estrogen receptor positive (ER+) breast cancers. Additionally, multiple studies have shown the knockdown of NAT1, by both small molecule inhibition and siRNA methods, in breast cancer cells leads to decreased invasive ability and proliferation and decreased anchorage-independent colony formation. However, the exact mechanism by which NAT1 expression affects cancer risk and progression remains unclear. Additionally, consequences …

Evaluation Of Drug-Loaded Gold Nanoparticle Cytotoxicity As A Function Of Tumor Tissue Heterogeneity., Hunter Allan Miller

Electronic Theses and Dissertations

The inherent heterogeneity of tumor tissue presents a major challenge to nanoparticle-medicated drug delivery. This heterogeneity spans from the molecular to the cellular (cell types) and to the tissue (vasculature, extra-cellular matrix) scales. Here we employ computational modeling to evaluate therapeutic response as a function of vascular-induced tumor tissue heterogeneity. Using data with three-layered gold nanoparticles loaded with cisplatin, nanotherapy is simulated with different levels of tissue heterogeneity, and the treatment response is measured in terms of tumor regression. The results show that tumor vascular density non-trivially influences the nanoparticle uptake and washout, and the associated tissue response. The drug …

Hiv Integrase Inhibitor Pharmacogenetics And Clinical Outcomes: An Exploratory Association Study, Derek E. Murrell

Electronic Theses and Dissertations

As HIV is now primarily a chronic condition, treatment is given life-long with changes as necessitated by alterations in tolerability and efficacy. Thus, personalized medicine may be useful in the prevention of unnecessary drug exposure and avoidable side effects. Three of the four currently available HIV integrase strand transfer inhibitors (INSTIs), raltegravir, elvitegravir, and dolutegravir, are widely utilized antiretrovirals in the USA and exhibit variations in outcomes among subjects. To interrogate differences among subjects receiving these drugs, we investigated the association of several single nucleotide polymorphisms (SNPs) with drug exposure, clinical outcomes, and subject-reported adverse events. HIV+ adults (≥18 years …

Melatonin-Micronutrients Osteopenia Treatment Study (Mots): A Translational Study Assessing The Effects Of Melatonin, Strontium Citrate, Vitamin D3 And Vitamin K2 On Bone Density, Bone Turnover Markers And Health-Related Quality Of Life In Postmenopausal Osteopenic Women Following A One-Year Double-Blind Randomized Placebo-Controlled Trial And On Osteoblast-Osteoclast Co-Cultures, Sifat Maria

Electronic Theses and Dissertations

Objective: The purpose of this study was to assess if a novel combination of melatonin and three other natural bone-aiding micronutrients: strontium citrate, vitamins D₃ and K₂ (MSDK) could improve bone health by modulating the activity of osteoblasts and osteoclasts in favor of balanced bone remodeling and by improving the overall health-related quality of life in postmenopausal osteopenic women.

Methods: The Melatonin-micronutrients Osteopenia Treatment Study (MOTS) is a translational research study that used both clinical and in vitro approaches to assess the efficacy of MSDK on bone health in women and to identify potential mechanisms for its effects. …

A Model To Study The Effects Of Whole Life Chronic Exposure To Arsenic Or Cadmium On The Development Of Adult Metabolic Syndrome : Initial Characterization Of Hepatic Changes., Jamie L. Young

Electronic Theses and Dissertations

Metabolic syndrome (MetS) is a group of diseases affecting < 30% of adults. Although obesity is a major risk for the development of MetS, it does not account for all cases, suggesting contribution of other risk factors. We hypothesized that early life exposure to arsenic (As) or cadmium (Cd) may represent such a risk. The purpose of this study was to characterize a model to discern the effects of early life exposures to Cd and As on high fat diet (HFD)-induced MetS. Adult C57BL/6J mice were exposed to control or metals containing drinking water. Pregnant dams and offspring were continuously exposed to the same toxicants as their parents. At weaning, offspring were fed LFD or HFD and sacrificed 10 or 24 weeks later. Metal exposure caused time- and sex-dependent alterations in HFD-induced variables of liver damage. The initial results suggest that these toxicants enhanced obesity-induced liver injury.

The Effects Of Polychlorinated Biphenyls Exposure On Non-Alcoholic Fatty Liver Disease : Role Of Aryl Hydrocarbon Receptor., Hongxue Shi

Electronic Theses and Dissertations

Polychlorinated biphenyls (PCBs) are detectable in serum of 100% of adults in US, and has been associated with fatty liver disease in epidemiological studies. PCBs are classified as either dioxin-like (DL) or non-dioxin-like (NDL) PCB based on their ability to activate the aryl hydrocarbon receptor (AhR). We used exposures that reflect human bioaccumulation patterns, which resembles Aroclor 1260 with a low level of the DL-PCB, PCB 126. Our aim was to determine if this exposure will activate the human and mouse AhR and examine if receptor activation influences these steatotic responses due to PCB exposures. DL-PCBs exposure-induced AhR activation in …

Vinyl Chloride Enhances Diet-Induced Liver Injury Via Metabolic Dyshomeostasis : Critical Role Of Mitochondria., Anna L. Lang

Electronic Theses and Dissertations

Background. Vinyl chloride (VC) is an environmental toxicant and has been shown to be directly hepatotoxic at high exposures. However, recent studies suggest low-level toxicant exposure can cause subtle changes to the liver. Given the high prevalence of non-alcoholic fatty liver disease (NAFLD) in the United States, it is important to determine the impact of low-level toxicant exposure on the progression of underlying liver injury when combined with other factors. Therefore, the overarching goal of this dissertation was to develop a model of VC co-exposure with high-fat diet (HFD) and to determine the mechanisms by which VC contributes to the …

Loss Of The Na+/H+ Exchange Regulatory Factor 1 Results In Increased Susceptibility To Cisplatin-Induced Acute Kidney Injury., Adrienne M. Bushau-Sprinkle

Electronic Theses and Dissertations

Background. Acute kidney injury (AKI), an abrupt loss of kidney function which carries a high mortality and confers an increased risk of chronic kidney disease, develops in 30% of patients who receive cisplatin, a widely used chemotherapeutic agent [1], [2], [3]. The sodium hydrogen exchange regulatory factor isoform 1 (NHERF1) is a scaffolding protein that anchors multiple membrane proteins, in renal proximal tubules [4]. NHERF-1 deficient mice have aberrant localization of BBM proteins in intracellular compartments [5]. The investigators have recently demonstrated NHERF1 deficient proximal tubule cells have an underlying …

The Combined Neuropharmacology And Toxicology Of Major 'Bath Salts' Constituents Mdpv, Mephedrone, And Methylone, Serena Allen

Electronic Theses and Dissertations

The synthetic cathinones, 3,4- methylenedioxypyrovalerone (MDPV), 4-methylmethcathinone (mephedrone), and 3,4- methylenedioxymethcathinone (methylone), gained worldwide notoriety as the psychoactive components of ‘bath salts;’ a marketing term used to circumvent federal drug laws and permit their legal sale. Previous studies have shown that these drugs share pharmacological characteristics with cocaine and the amphetamines, however, descriptions of their neurotoxic properties are limited. Moreover, while forensic analysis has revealed that the most frequently abused bath salts ‘brands’ contain binary and ternary mixtures of MDPV, mephedrone, and methylone, the majority of preclinical research has focused on explicating the individual effects of these drugs. Therefore, the …

Age-Related Host Factors Regulate Lung Cancer Progression., John Caleb Greenwell

Electronic Theses and Dissertations

Cancer is largely a disease of the elderly. In the United States alone, 87% of all cancers in 2017 will be diagnosed in individuals aged 50 years or older. Among them, lung cancer is the deadliest, accounting for 1 in 4 cancer deaths. The 5-year survival rate is below 20%, a number which has not changed substantially over the past several decades. This underscores a desperate need for new strategies in prevention, early detection and treatment of this deadly disease. While tobacco use is unquestionably the number one risk factor for the development of lung cancer, the majority of diagnoses …

Novel Insight Into The Liver-Lung Axis In Alcohol-Enhanced Acute Lung Injury., Lauren G. Poole

Electronic Theses and Dissertations

Background. Individuals who chronically abuse alcohol are almost 4 times more likely to develop Acute Respiratory Distress Syndrome (ARDS), the most severe form of Acute Lung Injury (ALI), but the mechanisms by which alcohol abuse sensitizes the lung to injury are poorly understood. However, the lung appears to share many parallel mechanisms of injury with the liver- a primary target of alcohol abuse. The overarching goal of this dissertation was therefore to expand on established mechanisms of alcohol-induced liver injury to ask innovative questions about mechanisms of alcohol-enhanced acute lung injury, as well as to develop new tools that may …