Medicine and Health Sciences Commons^™

Computer-Aided Drug Discovery For Helicobacter Pylori, Nicole Ann Vita

Theses and Dissertations (ETD)

Helicobacter pylori is a high-priority drug-resistant pathogen and is currently the only bacteria considered to be a class I carcinogen and there is a critical need to identify novel chemical matter to treat H. pylori infections. Hp is responsible for greater than 60% of gastric cancer related deaths and 89% of all gastric cancer morbidities. In a previous study, our lab identified novel Hp thienopyrmidine inhibitors that target respiratory complex I, an essential enzyme in respiration. Respiratory complex I is a large asymmetric multidomain and membrane bound enzyme and due to these innate features, it is not practical for biophysical …

Model-Based Dose-Exposure-Response Assessment For Lead And Backup Spectinamide In A Mouse Model Of Tuberculosis, Santosh Janardan Wagh

Theses and Dissertations (ETD)

Despite decades of research, tuberculosis remains the oldest pathogen-based disease that is the leading cause of death from a single infectious agent. Among many anti-tubercular therapies under investigation, the semisynthetic compounds spectinamides are a promising novel class of anti-tuberculosis agents. One such lead candidate, spectinamide 1810, and backup spectinamide 1599 have demonstrated excellent efficacy, safety, and drug-like properties in various in vitro and in vivo assessments. The dose-ranging and dose fractionation studies were designed to characterize the dose-exposure-response relationship for lead and backup spectinamide in a mouse model of Mycobacterium tuberculosis infection. In this current study, we used 26 and …

Vitamin D Levels Affect Survival In A Bcr-Abl Acute Lymphoblastic Leukemia Mouse Model But Do Not Cause Vitamin-Drug Interactions, Kavya Annu

Theses and Dissertations (ETD)

It is a well-established phenomenon that dietary components containing CYP3A inducers or inhibitors if co-administered with drugs that are CYP3A4 substrates lead to marked drug-drug interactions. Because vitamin D is known to regulate intestinal CYP3A expression and gut CYP3A expression plays an important role in pre-systemic metabolism of CYP3A drugs, we determined the impact of vitamin D (VD3) status on systemic exposure and efficacy of chemotherapeutic agents that are CYP3A substrates. We employed VD3 sufficient and deficient mice to perform pharmacokinetics (PK) and anti-leukemic efficacy studies.

First, using hCYP3A4 transgenic mouse model we evaluated the intestinal, hepatic and renal expression …

Veru-111 As An Oral Tubulin Inhibitor Suppressing Triple-Negative Breast Cancer And Evaluation Of Novel Tubulin Inhibitors For Cancer Therapy, Shanshan Deng

Theses and Dissertations (ETD)

Triple negative breast cancer (TNBC) has aggressive clinical features strongly associated with poorer overall prognosis and higher mortality rates relative to other molecular subtypes. FDA-approved drugs, such as paclitaxel, are effective in treating TNBC. Yet, treatment failure is commonly observed due to the development of acquired chemoresistance, which remains a clinical challenge for TNBC therapy.

Development Of Multiple Microemulsion Eye Drops For Sustained Release Of New Glaucoma Drug, Doaa Nabih Ahmed Maria

Theses and Dissertations (ETD)

Persistent or repeated elevation of intraocular pressure (IOP) is a primary risk factor of visual field loss in glaucoma, therefore IOP reduction is the first-line therapeutic option in the disease management. Unfortunately, the current therapies are associated with a lot of deficiencies including several daily dosing, reduced efficacy and systemic side effects all of which resulted in poor patient compliance. Previously we have identified Calcium voltage-gated channel auxiliary subunit Alpha2delta 1 gene (Cacna2d1) as a novel modulator of IOP and confirmed that pregabalin targeted CACNA2D1 in eye tissues (ciliary body and trabecular meshwork) to lower IOP in a …

Novel Determinants That Influence Azole Susceptibility In Candida Glabrata And Candida Albicans, Sarah Garland Whaley

Theses and Dissertations (ETD)

Despite the scientific and medical communities’ best efforts, the incidence of fungal infections in susceptible populations continues to rise. The most common cause of these opportunistic fungal infections is Candida. In fact, Candida is the fourth most common pathogen associated with nosocomial blood stream infections. Reported mortality rates for patients with candidemia vary, but have not decreased in the past fifteen years and are reported to be as high as 50%. Candida glabrata, second only to Candida albicans among Candida infections, expresses high rates of resistance to treatment with arguably the best class of currently available antifungals - …

Characterization Of The Hepatotoxicity Of Rifampicin And Isoniazid, Christopher T. Brewer

Theses and Dissertations (ETD)

In a mouse model, rifampicin and isoniazid combination treatment results in cholestatic liver injury that is associated with an increase of protoporphyrin ix (PPIX), the penultimate heme precursor. Excess PPIX is believed to bind to bile acids, precipitate in bile canaliculi, and form bile plugs leading to cholestasis fol owed by liver injury. Both ferrochelatase (FECH/Fech) and aminolevulinic acid synthase 1 (ALAS1/Alas1) are crucial enzymes in regulating heme biosynthesis. Isoniazid has recently been reported to up-regulate Alas1 but down-regulate Fech protein levels in mice; however the mechanism of isoniazid mediated heme synthesis …

Discovery Of Novel Tubulin Inhibitors And Selective Survivin Inhibitors For Advanced Melanoma And Total Synthesis Of Bioactive 20s-Hydroxyvitamin D3, Qinghui Wang

Theses and Dissertations (ETD)

According to the statistics from American Cancer Society, the 5-year survival rate for patients with advanced melanoma is as low as 5%. Treatment of advanced melanoma, therefore, represents an unmet medical need. In this dissertation, I will show the effort to develop new generations of bioavailable tubulin inhibitors targeting the colchicine binding site and selective small-molecule survivin inhibitors for treating advanced melanoma. Extensive structure-activity relationship (SAR) studies of lead molecules ABI-231 and UC-112 have been performed.

Chapter 1 will introduce the current situation of advanced or metastatic melanoma, its clinical drug treatments, as well as problems in current drug treatments. …

Synthesis Of 20s-Hydroxyvitamin D3 Analogs And Their 1Α-Hydroxyl Derivatives As Potent Anti-Inflammatory Agents, Zongtao Lin

Theses and Dissertations (ETD)

Rheumatoid arthritis (RA) is one of the autoimmune diseases, and is affecting 2.5 million Americans in total. Among the treatment options of RA, 1α,25-dihydroxyvitamin D3 [1,25(OH)2D3] is the only steroidal drug used clinically for anti-inflammatory and immune diseases. However, long-term use of 1,25(OH)2D3 (625 µg/day) in human would result in hypercalcemia (toxicity), and 1,25(OH)2D3 has substantial hypercalcemic effects (toxicity) in mice at a dose as low as only 2 µg/kg. Fortunately, during the investigation of novel metabolic pathway of vitamin D3 by cytochrome P450 enzymes, we found 20S-hydroxyvitamin D3 [20S(OH)D3] as a good lead compound. 20S(OH)D3 suppressed disease symptoms at …

Age-Associated Expression Patterns Of Oatp 1b1 And Oatp 1b3 And Their Effect On The Disposition Of Fexofenadine, Margaret Mary Thomson

Theses and Dissertations (ETD)

As part of the drug disposition process (absorption, distribution, metabolism, excretion), an often overlooked aspect is transport. In order for drugs to be metabolized and excreted from the body they go through the liver or other drug removal organs. For drugs that are polar or are large they must rely upon transport mechanisms to transport them across the biomembranes of the drug removal organs. OATP1B1 and OATP1B3 are transporters on the sinusoidal membrane of the liver which work in concert with the drug metabolizing enzymes as part of the drug removal process. It is known that the development of each …

Design, Synthesis, And Evaluation Of Novel Positron Emission Tomography Radiotracers, Christopher Philip Surdock

Theses and Dissertations (ETD)

Neuroblastoma (NB) is the most common extracranial tumor in patients under 1 year of age and it constitutes about 8-10% of all childhood cancer. It originates from neural crest cells that normally differentiate to form the sympathetic ganglia, adrenal medulla and other paraspinal sites where sympathetic nervous system tissue is present. Even with an extensive treatment regimen that typically includes surgery, chemotherapy, total body irradiation and autologous stem cell transplantation, the 5-year event-free survival is <50% for high risk patients, and there are numerous long-term side effects associated with treatment. This body of work investigated two projects for improving patient outcomes through the development of positron emission tomography (PET) radiotracers that could be used for therapy planning. The goal of the first project was to design, synthesize, and evaluate PET radiotracers that could measure the enzymatic activation of Irinotecan (CPT-11), a potent chemotherapeutic used in the treatment of colon cancer and several pediatric solid tumors. CPT-11 itself is a prodrug which is converted in vivo to SN-38, via metabolism by carboxylesterase (CE) enzymes. St. Jude Children’s Research Hospital researchers have designed a two-pronged protocol of tumor-targeted CPT-11 chemotherapy combining the complementary approaches of a) specific modulation of human CE in normal tissues to improve drug delivery, and b) tumor-targeted activation of prodrug using neural progenitor cells (NPC) transfected with a mutant human CE cDNA. The tumor-selective trafficking of NPC allows over-expression of CE within the tumor. This prodrug/activating enzyme therapeutic approach has shown extremely encouraging preclinical results in the treatment of NB (90% 1-year survival in mice). However, successful translation of this novel therapeutic approach into general clinical practice requires a better understanding of progenitor cell trafficking, duration and intensity of enzymatic activity and the ultimate biological fate of the therapeutic construct. Toward this end, PET radiotracers were developed based on extensive structure-activity relationship (SAR) studies of CE binding. The goal of the second project was to design, synthesize, and evaluate PET radiotracers that could identify the presence of the tropomyosin receptor kinase B (TrkB). TrkB is not normally found in sympathetic nervous tissue, which is the tissue NB develops from, and thus is a potential target for imaging and therapy. The presence of TrkB and its neurotrophin, brain derived neurotrophic factor (BDNF), have been reported to protect neuroblastoma tumor cells from chemotherapy-induced apoptosis via a phosphatidylinositol 3’-kinase pathway. Radiotracers were synthesized and evaluated for their ability to identify TrkB both in vitro and in vivo. PET radiosynthetic procedures were optimized to synthesize novel radiotracers for imaging targets that could help clinicians monitor therapy or identify markers that would aid in therapy planning for NB patients. The method development could be applied to future compounds that show improved chemical characteristics for synthesis and selectivity.

Cannabinoid Receptor 2 (Cb2) Ligands Downregulate Pro-Inflammatory Markers In Stimulated Primary Human Periodontal Ligament Fibroblasts (Hpdlfs), Ammaar Hasan Abidi

Theses and Dissertations (ETD)

There are approximately 743 million individuals suffering from chronic periodontitis (PD) making it the sixth most prevalent condition worldwide. The affected adult population in the U.S. are nearly 64.7 million and the healthcare costs exceeds $14 billion. Recently, host response to pathogenic infection has been seen critical to the progression of PD and exhibit increase in various inflammatory markers. Marijuana is well known for its recreational usage and is a risk factor for periodontal disease, which is seen as a concern in society for its negative health consequences. However, many medical conditions can benefit from the pharmacological effects of cannabinoids. …

Discovery Of Natural Product-Based Antimycobacterial Agents Effective Against Non-Replicating Bacilli, Shajila Siricilla

Theses and Dissertations (ETD)

New antimycobacterial molecules that kill non-replicating Mycobacterium tuberculosis (Mtb) were identified by screening libraries of synthetic natural products. De novo screening of a 400-membered library of aurachin RE analogs resulted in discovery of UT-317 ((R)-20). UT-317 is a selective vitamin K2 biosynthesis (MenA) inhibitor that killed replicating and non-replicating Mtb at 2.31 μg/mL (MIC) and 0.85 μg/mL, respectively. A 50-membered library of capuramycin analogs was evaluated in their enzymatic inhibitory activities against translocase I (MraY/MurX) and prenyl-phosphate-GlcNAc-1-phosphate transferase (WecA). UT-01320 (45) is identified as a selective WecA inhibitor that kills both replicating and non-replicating Mtb at 1.50 μg/mL (MIC) and …

Biophysical And Biochemical Screening Approaches For Antimicrobial Drug Discovery Targeting S. Aureus Clpp, Aman Preet Singh

Theses and Dissertations (ETD)

The discovery of antibacterial drugs has been among most significant achievements of mankind in saving millions of lives across the planet from infectious diseases. With rise in resistance to almost all existing chemotypes, the design of next generation novel antibiotics has become much more challenging and difficult. The early 21st century witnessed the advancement of multiple novel chemotypes during golden age of antibiotics however the pace of antibiotic drug discovery has slowed down tremendously, contributing to life threatening antimicrobial discovery void since 1980’s. Therefore the need to develop novel antibiotics with unique mechanism of action to leverage against multi drug …

Antibiotic Drug Discovery With An Eye Towards Overcoming Drug Resistance, Daniel Towner Hoagland

Theses and Dissertations (ETD)

As a species, humans have become ever reliant on the use of antibiotics to facilitate our everyday lives. The widespread emergence of resistance to currently used antibiotics is commonly attributed to an over use in our society. Such resistance, coupled with a lack of innovation and production of novel antibiotic drugs, threatens to return humanity to an era similar to one before the discovery of the first antibiotics. The need to find new agents to be used in this fight is paramount, as well as learning from our recent failures to produce such compounds. This document will highlight my efforts …

Repeated Zolpidem Treatment Effects On Sedative Tolerance, Withdrawal, Mrna Levels, And Protein Expression, Brittany T. Wright

Theses and Dissertations (ETD)

Zolpidem and benzodiazepines (BZs) potentiate the inhibitory action of gamma-Aminobutyric acid (GABA) by allosterically binding to GABAA receptors (GABAAR). Prolonged use of GABAAR positive allosteric modulators (PAM) can lead to behavioral tolerance, the diminished response to the same drug dose with repeated use, and withdrawal, a group of symptoms that occur due to abrupt end of drug treatment. Zolpidem is a short-acting, non-BZ GABAAR PAM whose potential for tolerance and withdrawal is unclear. Zolpidem demonstrates sedative efficacy similar to BZs and has become a main treatment of insomnia in lieu of BZs. Zolpidem replaced BZs due to lower incidences of …

Hit Identification For Pkcζ Inhibitors: Structure-Based Optimization, Virtual Screening, And Biological Evaluation, Xiaoxin Wu

Theses and Dissertations (ETD)

Protein kinase C ζ (PKCζ) is believed to be a promising target for the treatment of some diseases, including inflammatory diseases, obesity and diabetes. Hit identification of PKCζ inhibitors was conducted by structure-based modification, virtual screening and biological evaluation. Among all the compounds selected and synthesized, compound JW-1-60A showed moderate activity against PKCζ at 30 μM and 100 μM. The molecular modeling studies showed that the binding mode of JW-1-61A was very close to the binding mode of JP-3-149, a reported PKCζ inhibitor with very potent activity, which might partially explain the moderate activity of JW-1-61A. Based on the structure …

Optimization Of Lead Spectinamide Compounds As Novel Anti-Tuberculosis Agents With A Pharmacometric Approach, Ashit Rasendu Trivedi

Theses and Dissertations (ETD)

In an effort to combat the global Tuberculosis pandemic, Dr.Richard E. Lee and his group at St.Jude Children’s Research Hospital designed a novel series of anti-tuberculosis agents, spectinamides – semi-synthetic analogs of spectinomycin. Spectinamides are a potent inhibitor of mycobacterial ribosomes and overcome efflux mediated drug resistance in M. tb. Spectinamides have shown an excellent in vitro activity, which makes them well suited for further lead optimization and preclinical development. We hypothesized that through pharmacokinetic (PK) and pharmacodynamics (PD) model-based dosing optimization studies, we could strategically guide the selection and refinement of more potent and effective anti-TB spectinamides. Biopharmaceutical in …

Development And Evaluation Of Amphotericin B Loaded Iron Oxide Nanoparticles For Targeted Drug Delivery To Systemic Fungal Infections, Pavan Balabathula

Theses and Dissertations (ETD)

A targeted nanotheronostic drug delivery system to diagnose and treat life threatening invasive fungal infections (IFIs) such as cryptococcal meningitis was designed, developed, characterized, and evaluated. To address the development processes, first, iron oxide nanoparticles (IONP) (34-40 nm) coated with bovine serum albumin (BSA), loaded and targeted with amphotericin B (AMB) (AMB-IONP) was formulated by applying a layer by layer approach. Several designs (A, B, C, D, & E) of AMB-IONP were developed and their physicochemical properties such as drug loading with HPLC method, particle size, poly dispersity index (PDI), and ζ-potential using dynamic light scattering (DLS) technique, morphology with …

Discovery Of Novel Tubulin Polymerization Inhibitors And Survivin Inhibitors As Potential Anticancer Agents, Min Xiao

Theses and Dissertations (ETD)

Melanoma is the most dangerous form of skin cancer and accounts for the majority of skin cancer death. Although considerable advances have been made in melanoma treatment in recent years, there are many problems associated with current therapies. Drug resistance to targeted therapies is almost inevitable after short term treatment. Immunotherapies generally have low response rate and the effects vary among patients. Therefore, the need to develop new and more effective treatment for melanoma is high.

The work presented here focuses on discovery of novel anticancer agents for melanoma by targeting two important cancer targets: tubulin and survivin. Microtubules play …

Challenges In The Pharmacokinetics Of Therapeutic Proteins, Wararat Limothai

Theses and Dissertations (ETD)

Due to the complex structure and complicated disposition pattern of therapeutic macromolecules, their pharmacokinetic interpretation has many challenges. Two of these challenges were investigated in this dissertation: 1) the error of classical bioavailability assessment observed during subcutaneous (SC) administration of therapeutic macromolecules that undergo target-mediated drug disposition (TMDD) and 2) the ontogeny of the neonatal Fc receptor (FcRn) expression along with its effect on the pharmacokinetics of monoclonal antibodies (mAbs) during development.

TMDD often well describes the pharmacokinetics of therapeutic proteins that have high specificity and affinity of binding to their target receptors. The target receptors can be saturated by …

Overcoming Acquired Resistance To Braf Inhibitors By Novel Synergistic Drug Combination And Discovery Of Novel Smac Mimetics As Selective Survivin Inhibitors, Jin Wang

Theses and Dissertations (ETD)

The first part (Chapter 1 and 2) of this dissertation presents a novel combination study of melanoma therapy. Acquired clinical resistance to vemurafenib, a selective BRAFV600E inhibitor, arises frequently after short term chemotherapy. Since the inhibitions of targets in the RAFMEK-ERK pathway result in G0/G1 cell cycle arrest, vemurafenib-resistant cancer cells are expected to escape this cell cycle arrest and progress to subsequent G2/M phase. We hypothesized that a combined therapy using vemurafenib with a G2/M phase blocking agent will trap resistant cells and overcome vemurafenib resistance. To test this hypothesis, we first determined the combination index (CI) values of …

Functional Activity And Switching Of Novel Cannabinergic Ligands, Bret Alan Koertge

Theses and Dissertations (ETD)

Pursuant to the discovery of the cannabinoid receptors, research in this field has grown exponentially over the last 2 decades. With their utility in various disease states such as heart disease, cancer, stroke, neurodegenerative and inflammation, cannabinoids stand poised to become a great therapeutic agent. This research seeks to better understand the functional mechanism of cannabinoids, in the hopes of ascertaining which molecular attributes confer desirable selectivity and functional activity.

Looking first at classical benzchromene core analogues, we have shown that presence of an aromatic substitution at C-1' imparts a CB1 agonist, CB2 antagonist. This is a unique mechanism and …

Computer-Aided Drug Design And Discovery, Screening And Synthesis Of Small Molecule Inhibitors Of Nucleoside Transporters, Hilaire Colleen Playa

Theses and Dissertations (ETD)

Using prior biological data, pharmacophore models were made for hCNT1, hCNT3, hENT1, and hENT4. The hCNT3 and hCNT1 pharmacophore were used to select compounds for biological testing. The NBMPR analogue and dipyridamole analogue hENT1 pharmacophores were compared to each other and to a combined pharmacophore for hENT1. The dipyridamole analogue pharmacophore better predicted non-nucleoside small molecule inhibitors, and as such appears to be the better tool for aiding in the design of new small molecule inhibitors. The hCNT3 pharmacophore failed to select active compounds and as such must be redesigned. The hCNT1 pharmacophore succeeded in identifying two moderately active compounds …

Glioma: A Tale Of Corticosteroids, Thiopurines And Proposed Novel Antiglioma Small Molecules, Amira Ahmed

Theses and Dissertations (ETD)

Glioma is a brain tumor that arises from glial cells or glial progenitor cells, and represents 80% of malignant brain tumor incidence in the United States. Glioblastoma multiforme (GBM) is the most aggressive primary brain tumor malignancy with fewer than 8% of patients with GBM surviving for 3 years. Over the past 10 years, despite improvement in diagnosis and therapies for cancer, the survival rate for high-grade glioma patients remains unchanged. The main focus of this dissertation is to investigate two therapeutic agents that are related to increase tumor resistance or increase secondary tumor incidence, which might play a role …

Erg11-Mediated Azole Resistance In Candida Albicans, Stephanie Ann Flowers

Theses and Dissertations (ETD)

Although many medically important Candida species are commensal to the gut or colonizers of the skin, these organisms have the propensity to cause disease in the event of a waning immune system. Clinical manifestations of infections with Candida species can range from superficial mucosal infections to deep organ involvement usually resulting from haematogenous spread of infection. Despite significant progress made in the management of patients with fungal infections, the emergence of antifungal resistant clinical isolates creates significant problem in regards to antifungal prophylaxis and empirical treatment strategies. Antifungal resistance is associated with high mortality rates and hefty medical costs. The …

A Series Of Pharmaceutical Technology Concepts Applied To Pediatric Formulations, Hao Lou

Theses and Dissertations (ETD)

Pediatric formulations have received great attention from regulatory agencies in the United States and Europe. Since solid dosage forms such as tablets and capsules will not be able to improve pediatric patients’ compliance, customized pediatric formulations are needed. In response, formulators in the pharmaceutical industry have made significant effort into developing various pediatric formulations. However, developing satisfactory pediatric formulations is a process that is guided by case by case basis. The objective of this current study was to apply the scientific pharmaceutical technology concepts into developing modern pediatric formulations. We have shown that the drug delivery design will be affected …

High Resolution Mass Spectrometry (Hrms) Based Investigation Of Small Molecule, Bioactive Secondary Metabolites As Probes In The Examination Of Bacterial Resistance And Virulence, Jerrod Stephen Scarborough

Theses and Dissertations (ETD)

The widespread availability of antimicrobial chemotherapeutics over the last half of the twentieth century has offered dramatic increases in life expectancy. Unfortunately, many pathogenic agents are exhibiting ever increasing resistance to many frontline antibiotics. New chemotherapeutic agents are urgently needed to combat this threat; this work seeks to illustrate applications in which mass spectrometric techniques may be applied to the investigation of novel, small molecule chemotherapeutics for the treatment of bacterial infections. Chapter 1 contains an introduction to mass spectrometry, as well as an overview of relevant chromatographic techniques. Chapter 2 introduces the bacterium F tularensis and M ulcerans and …

Development Of The Sustained Release Analgesic Formulations For Rodents And A Novel In Vitro Model For Parenteral Formulations With The Character Of A Level A Ivivc, Jin Xu

Theses and Dissertations (ETD)

Laboratory animals are often subjected to various painful surgical procedures such as laparotomy, thoracotomy or orthopedic procedures as well as non-surgical procedures such as the induction of arthritis. Any procedure that causes pain in humans is assumed to cause pain in animals too. It is the ethical obligation of all research personnel to reduce or preferably eliminate pain and distress by using analgesics. Furthermore, the Institutional Animal Care and Use Committee (IACUC) requires that appropriate anesthetics and/or analgesics must be used to minimize or eliminate pain and distress for animals undergoing painful procedures.

The oral administration route is the most …

Inhibition Of Breast Cancer Angiogenesis And Metastasis Ay Targeting Hypoxia-Inducible Factor-1Α, Chikezie O. Madu

Theses and Dissertations (ETD)

The current clinical chemotherapy agents are not ideal for breast cancer as they are not curative, but only provide a modest extension of survival with sometimes a severely adverse effect on the patient’s quality of life. There is, therefore, an urgent need to search for new and more effective anti-breast cancer drugs. However, the existing screening system is inefficient and time-consuming despite the extremely large amount of small molecule compounds in database currently available, and thereby hindering the effort for selecting new and effective anti-cancer drugs.

The majority of locally advanced solid tumors contain regions of reduced oxygen availability. Hypoxia …