Medicine and Health Sciences Commons^™

Evaluation Of Human Stem Cell-Derived Neurons In 2d And 3d Cultures For Neurodevelopmental Studies, Epilepsy Disease Modeling And Drug Discovery, Hamed Salmanzadeh-Dozdabi

University of the Pacific Theses and Dissertations

Human stem cells have revolutionized the study of early neural development, offering a powerful tool to investigate the complex processes involved in the formation of the nervous system. In this study, the human pluripotent stem cell line, TERA2.cl.SP12, was utilized to derive neuroglial cells and to determine their differentiation and functional maturation up to one year in culture; this model was then investigated as a new tool for the study of neurodevelopmental toxicity, for seizure modeling and as a screening method for the investigation of new anticonvulsants. Immunocytochemistry experiments determined that non-differentiated cells expressed the stem cell marker Oct-3/4 and, …

Targeting Ribonucleotide Reductase For Breast Cancer Treatment, Nahid Sultana

University of the Pacific Theses and Dissertations

Breast cancer is the second most common type of cancer in the world. Hormone receptor (HR) positive breast cancer (BC) is a prevalent disease accounting for approximately 2 million new cases globally. Almost 70-80% of breast cancer patients are women with a positive score for the estrogen receptor (ER). Triple-negative breast cancer (TNBC) which have a negative score for estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor type 2 (HER2) is considered an aggressive histological breast cancer subtype with limited treatment options.Frequently, doxorubicin (DOXO)-based chemotherapy is utilized in this patient population due to the lack of …

Investigating Bzip Recognition Of Dna Sequences Through A Knob-Socket Perspective, Aaron Tran

University of the Pacific Theses and Dissertations

To investigate whether higher order packing interactions confer protein-DNA specificity, a modified Knob-Socket (KS) model was used to analyze the interface of bZIP-DNA crystal structures. The KS analysis identified a nine-residue quadripartite recognition core consisting of four contiguous KS pockets P1, P2, N3, and N4 that each pack one of the four DNA half-site bases in the target sequence. Only one base per base pair packs, and these interactions are split across the DNA strands: the first two positive strand positions 1p and 2p pack into P1 and P2 while the last two negative strand positions 3n and 4n pack …

Role Of Cysteine Redox State In Altering The Epithelial-Mesenchymal Transition In Lung Cancer, Md Anisur Rahman

University of the Pacific Theses and Dissertations

Epithelial-mesenchymal transition is a process by which cancer cells increase their capability for metastasis. EMT involves conversion of epithelial cells into a mesenchymal phenotype which makes cancer cells more invasive and motile. Lung cancer has the highest mortality rate among different types of cancers globally. Lung cancer exists in various types, the most prevalent of which is non-small cell lung cancer (NSCLC). Several factors, including oxidative stress, can induce EMT in cancer cells. However, the mechanism of how reactive oxygen species (ROS)-induced changes in cysteine redox state affect EMT remains elusive. Our studies aim to understand this mechanism by inducing …

Optimizing The Human Aryl Hydrocarbon Receptor (Hahr) Expression In Pichia Pastoris, Junyu Qian

University of the Pacific Theses and Dissertations

The aryl hydrocarbon receptor (AHR) is a transcription factor which heterodimerizes with the aryl hydrocarbon receptor nuclear translocator (Arnt) to regulate downstream gene transcription. For the purpose of studying the crystal structure of human aryl hydrocarbon receptor (hAHR), it is essential to obtain abundant amount of pure recombinant protein.Basing on the benefits of using P. pastoris system to produce recombinant protein, including appropriate folding, secretion of interest proteins to the external environment of the cell, and easier purification process of protein due to the its limited production of endogenous secretory proteins [1], our lab chose P. pastoris yeast as the …

Thermodynamic Mechanisms Of Helix Stabilization In A Model Peptide And Protein, Ryan Murray

University of the Pacific Theses and Dissertations

Biologics are large, complex therapeutic agents generally produced from living organisms. One group of biologics is peptide/protein based. Biological agents offer unique advantages over traditional therapeutics including longer half-lives, higher specificity, greater efficacy, and reduced off-target effects. However, protein/peptide based drugs suffer from both delivery and stability issues. The higher order of protein structures (secondary, tertiary, etc.) derive ~80% of their conformational stability from paltry hydrophobic effects, with net stabilization of 5-15 kcal/mole observed for many proteins. Loss of conformational stability can lead to increased aggregation, precipitation, and degradation; and reduced activity and side effects. To increase stability and improve …

The Combinatory Effects Of Pediatric Obesity And Ontogeny On Monocarboxylate Transporter Expression In Tissues Of Drug Disposition, Michael Ng

University of the Pacific Theses and Dissertations

Proton-coupled and sodium-dependent monocarboxylate transporters are encoded by the SLC16A and SLC5A gene family of solute carriers, and are responsible for the transport of essential nutrients such as L-lactate, pyruvate, and ketone bodies. Basigin, or CD147, acts as an ancillary protein for MCT1 and MCT4, and is involved in membrane surface expression of transporters. MCT's are also involved in the shuttling of monocarboxylic xenobiotics across cell membranes, including the drugs valproate and gamma hydroxybutyrate. MCT’s are also important for normal mammalian development, particularly during embryogenesis and early neonatal life. Previous studies have shown that ketogenic diets increase MCT expression in …

Optimization Of The Structure Of Ttr Ligands For Half-Life Extension (Tlhe), Guanming Jiang

University of the Pacific Theses and Dissertations

Many potential therapeutic agents face challenges for their clinical development due to short circulation half-life. As a result, prolonging the half-life of therapeutic drugs in circulation while preserving their hydrophilicity and small size will be a key step toward more effective and safe pharmacological molecules. Our lab developed a new approach for enhancing the safety and efficacy of therapeutic agents. By endowing therapeutic agents with a hydrophilic small molecule (a derivative of the clinical candidate, AG10) which reversibly binds to the serum protein transthyretin (TTR), the half-life of the therapeutic agent should be extended by binding to the TTR in …

Expression Of Mouse Full-Length Aryl Hydrocarbon Receptor And Human Aryl Hydrocarbon Receptor Ligand Binding Domain In Pichia Pastoris, Yiyuan Wang

University of the Pacific Theses and Dissertations

Aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that regulates biological responses to planar aromatic hydrocarbon. AHR activates gene transcription by binding to its corresponding enhancer with its partner-aryl hydrocarbon receptor nuclear translocator (ARNT). In addition, this receptor has been shown to regulate xenobiotic-metabolizing enzymes such as cytochrome P450. AHR exists widely in body tissues and affects bioactivation of carcinogenic compounds, T cell differentiation, fatty acid synthesis, cell proliferation, hematopoietic stem cell differentiation, respiratory reactivity, and insulin sensitivity. Although the precise mechanism illustrating the endogenous AHR function remains unclear, there has been intense interest in exploring AHR as a …

Incorporating Glutamic Acid-Valine-Citrulline Linker In Trifunctional Molecules Targeting Psma Ensures Enhanced Stability, Safety, And Efficacy In Mouse Model Of Prostate Cancer, Toufiq Ul Amin

University of the Pacific Theses and Dissertations

This project describes the development of a new antitumor therapeutic platform that combines the benefits of small-molecule drug conjugates (SMDCs) and antibody drug conjugates (ADCs). Valine-citrulline (VCit) dipeptide linkers are popular cathepsin B cleavable ADC linkers. Due to its instability in mouse serum, translating efficacy data from mouse to human is more difficult. It has been reported that replacing the VCit linker with glutamic acid-valine-citrulline (EVCit) improves ADC stability in mouse serum. The effect of the EVCit linker on the stability of SMDCs has not been reported so far. In a xenograft mouse model of prostate cancer, we found that …

Gc/Ms And Lc/Ms Approaches To Chemical Communication In Plants And Marine Cyanobacteria, Carolyn Keim

University of the Pacific Theses and Dissertations

Natural products are small organic compounds synthesized by living organisms including plants, animals, and microbes. These fall into one of two categories, primary metabolites are required for survival, but secondary metabolites usually play a more accessory role. Extracts from organisms have proven to be useful to humans throughout history. Prior to evidence-based western medicine practices, natural products were the only source of medicine and remain as a treatment source for underdeveloped nations. Today, natural products have either been approved by or have served as the template for many FDA approved drugs. Based on a survey of all FDA approved drugs …

The Vagabond Flourine Atom Revisited: Dissociative Photoionization Of Tri- And Pentafluoropropene, Jessica K. De La Cruz

University of the Pacific Theses and Dissertations

Photoelectron Photoion Coincidence (PEPICO) Spectroscopy studies on two unsaturated hydrofluorocarbons (HFCs), also known as hydrofluoroolefines (HFOs), are presented here. Previously, the Sztáray group has studied the dissociation of trans-1,3,3,3-tetrafluoroprop-1-ene (ElixClean), which is a fourth-generation refrigerant and propellant and has lower global warming potential than its precursors. My study is an extension of the ElixClean study as it aims to explore how the different number of fluorine atoms impact the dissociation reactions of these molecules. Both 3,3,3-trifluoropropene (TFP) and cis-1,2,3,3,3- pentafluoropropene (PFP) are also utilized as propellants and refrigerants.Measurements were carried out with remote access to the CRF-PEPICO (combustion reactions followed …

Investigation Of Cdk8 Inhibitor Q-12 Effects On Cdk8 And Cdk8 Substrates In Triple Negative Breast Cancer Cell Line Mda-Mb-468, Shengxi Li

University of the Pacific Theses and Dissertations

Cyclin-dependent kinases (CDKs) and cyclins (Cyclins) are the core molecules in the regulation mechanism of the entire cell cycle. Cell cycle dysregulation is a common feature of human cancers, and inhibitors of cyclin-dependent kinases (CDKs) play a crucial role in cell cycle control and are one of the most promising areas of cancer therapy. We aspired to use our cyclin-dependent kinase 8 (CDK8) inhibitor, Q-12, as a probe for biomarker discovery for CDK8 inhibitor sensitive tumor types. Q-12 shows potent inhibition of cell viability and induction of apoptosis process in some triple-negative breast cancer (TNBC) and colorectal cancer cell lines …

In Vitro Comparative Study Of The Binding Affinity And Targeted-Drug Delivery Efficiency Of Egfr-Targeting Peptides, Jingda Wang

University of the Pacific Theses and Dissertations

Peptides have been used as targeting ligands in targeted drug delivery. Conjugating peptides to cytotoxicity agents via a linker to build peptide-drug conjugate (PDC) is a promising targeting strategy. The binding affinity of the peptide ligand and the receptor plays a crucial role in the PDC targeted drug delivery. Although the ligand binding which can be used in targeted drug delivery has been established conceptually, the quantitative or semi-quantitative contribution of binding affinity in targeting efficiency has not been fully explored. The optimal range of binding affinity of the peptide for targeted delivery remains unknown. Therefore, there is a lack …

Development Of Miriplatin-Loaded Nanoparticles Against Non-Small Cell Lung Cancer, Zhongyue Yuan

University of the Pacific Theses and Dissertations

Lung cancer claims the highest mortality and the second-most estimated new cases among all oncological diseases [1]. Non-small cell lung cancer (NSCLC) accounts for approximately 85% of all newly diagnosed lung cancers [2]. Approximately 40% of newly diagnosed lung cancer patients are stage IV. For stage IIIB/IV NSCLC, cytotoxic combination chemotherapy is standard first-line chemotherapy. A regimen of platinum (cisplatin or carboplatin) plus paclitaxel, gemcitabine, docetaxel, vinorelbine, irinotecan, or pemetrexed is the recommended clinical treatment [3].

Cisplatin is the first-generation platinum-based anti-cancer drug. Although cisplatin is much more effective than other platinum drugs at the same dosage [4], accumulating reports …

Post-Translational Modification And Degradation Mechanisms Of The Aryl Hydrocarbon Receptor, Yujie Yang

University of the Pacific Theses and Dissertations

The aryl hydrocarbon receptor (AHR) is a transcription factor first discovered to be activated by exogenous ligands, such as dioxins, and helps promote downstream gene (e.g. CYP1A1) transcription to metabolize the toxicants. With the reports of various AHR targets genes, the expression levels and activities of AHR have been implicated in many physiological and pathological situations. Understanding how AHR protein level is regulated would provide more information to target AHR. AHR stays in the cytosol in the absence of ligand in a complex with HSP90, p23 and XAP2. After ligand activation, AHR translocates into the nucleus, fulfilling its transactivation function …

Translationally-Transformed Coupled-Cluster Theory For Periodic Systems, Boris Daniel Gutierrez-Cortes

University of the Pacific Theses and Dissertations

There are a lot of interesting problems in surface chemistry where quantum chemistry could give great insight, like reaction mechanisms in heterogeneous catalysis, the effect of surface functionalization on semiconductors, or the influence of defects on the reactivity of crystal surfaces.

Plane wave based methods applied to crystals cannot handle problems that are localized in nature like surface defects and adsorbates. On the other hand, molecular electronic structure techniques, which describe these effects and the locality of the electronic correlation well, are too computationally expensive to use on these systems.

In this work, we introduce translationally-transformed coupled-cluster (TT-CC) theory, a …

Investigating The Specificity Of Coiled-Coil Recognition, Melina Huey

University of the Pacific Theses and Dissertations

The bZIP transcription factors make up a family of long α-helical proteins that dimerize based on a pattern of hydrophobic residues and bind to DNA through a region of basic residues. Because binding specificity is a particular topic of interest, the dimerization interaction is attractive as a possible candidate to better understand protein quaternary structure. Use of the Knob-Socket (KS) model for determination of packing structure provides a novel approach to analyze protein-protein interactions. A KS analysis of the protein-protein interface provides unique insight into the specificity of the classical leucine zipper pseudo-7mer repeat. From an analysis of the KS …

Development Of Linked-Domain Protein Inhibitors Of The E2-Conjugating Enzyme Ube2d, Anneroos E. Nederstigt

University of the Pacific Theses and Dissertations

In most eukaryotic organisms, the ubiquitination pathway is one of the most important and versatile signaling systems in use. It is integral to processes such as protein degradation and homeostasis, DNA repair cell cycle regulation, signaling and regulation, epigenetics, and many more. Ubiquitin (Ub) is a short polypeptide of 8.6 kDa, 76 residues that functions as a reversible post-translation modification (PTM). It furthermore contains 7 different lysine residues (K6, K11, K27, K29, K33, K48, K63), all of which can form isopeptide linkages with one another to link individual Ub moieties to form unique polyUb chains onto substrates. The type of …

Bayesian-Derived Vancomycin Auc24h Threshold For Nephrotoxicity In Special Populations, Dan Ho

University of the Pacific Theses and Dissertations

A Bayesian-derived 24-hour area under the concentration-time curve over minimum inhibitory concentration from broth microdilution (AUC24h/MICBMD) ratio of 400 to 600 is recommended as the new monitoring parameter for vancomycin to optimize efficacy and minimize nephrotoxicity. The AUC24h threshold of 600 mg*h/L for nephrotoxicity was extrapolated from studies that assessed the general population. It is unclear if this upper threshold is consistent or varies when used in special populations such as critically ill patients, obese patients, patients with preexisting renal disease, and patients on concomitant nephrotoxins.The purpose of this study is to investigate the generalizability of the proposed vancomycin AUC24h …

Harnessing Transthyretin To Enhance The In Vivo Half-Life Of Human Interleukin-2 (Il-2), Fang Liu

University of the Pacific Theses and Dissertations

Protein therapeutics are available as cytokines, clotting factors, enzymes, hormones, growth factors, antibodies et al. They have been shown to be effective in treating a variety of important human diseases. Since human insulin was approved as the first recombinant protein therapeutic, this field has experienced rapid growth. One of the biggest challenges for protein therapeutics in clinical application is their short half-life. Except for monoclonal antibodies, which have serum half-life for weeks, most of the protein therapeutics have half-lives ranging from minutes to hours. Kidney filtration, proteasome degradation and liver metabolism are the main factors that attribute to their short …

Impact Of 17-Beta Estradiol And Moderate-Intensity Exercise On Mesenteric Arterial Function Of Uc Davis Type-2 Diabetes Mellitus Rats, Md Rahatullah Razan

University of the Pacific Theses and Dissertations

The studies in this dissertation were designed to investigate the impacts of estrogen (17-β estradiol/E2) and moderate-intensity exercise (MIE) on the mesenteric arterial (MA) function of the University of California Davis type-2 diabetes mellitus (UCD-T2DM) Rat model. Our recent report suggests that diabetes impairs MA vasorelaxation in both sexes of the UCD-T2DM model. Particularly, we reported that MA from prediabetic male rats showed a greater impairment compared to that in prediabetic females. However, when females become diabetic, they exhibit a greater vascular dysfunction than males. Therefore, the aim of the first study was to investigate whether female sex hormone, specifically …

Development Of Lipid-Based Nano Formulations Of Miriplatin Against Lung Cancer, Zizhao Xu

University of the Pacific Theses and Dissertations

Cancer is the second leading cause of death and is responsible for approximately 9.6 million deaths worldwide in 2018. Among all oncological diseases, lung cancer claims the highest mortality (male: 23.5%; female: 22%) and the second most new cases (male: 13%; female: 12%) in the US. Approximately 40% of newly diagnosed lung cancer patients are in the advanced stage IV, for which platinum-based chemotherapy is the first-line treatment, either by itself or in combination with surgery or radiotherapy.

Cisplatin, the first-generation platinum-based anticancer chemotherapeutic agent, has the highest potency against lung cancer but carries many severe adverse effects. Cisplatin also …

Elephant And Anchors ‒ Photoelectron Photoion Coincidence Spectroscopy Of Small Oxygenated Molecules, Apeter Weidner

University of the Pacific Theses and Dissertations

The dissociative photoionization reactions of two small, oxygenated organics, namely 1,3-dioxolane and methyl vinyl ketone, were studied by photoelectron photoion coincidence (PEPICO) spectroscopy. Experiments involving 1,3-dioxolane were carried out in the photon energy range of 9.5‒13.5 eV. The statistical thermodynamics model shows that a total of six dissociation channels are involved in the formation of three fragment ions, namely C3H5O2+ (m/z 73), C2H5O+ (m/z 45) and C2H4O+ (m/z 44), with two channels contributing to the formation of each. By comparing the results of ab initio quantum chemical calculations to the experimentally derived appearance energies of the fragment ions, the most …

Regulation Of Intracellular Aryl Hydrocarbon Receptor Protein Levels, Jinyun Chen

University of the Pacific Theses and Dissertations

The aryl hydrocarbon receptor (AHR) is a ligand-activated signaling molecule which controls tumor growth and metastasis, T cell differentiation, and liver development. Expression levels of this receptor protein are sensitive to the cellular p23 protein levels in immortalized cancer cell lines. As little as 30% reduction of the p23 cellular content can suppress the AHR function. Here we reported that down-regulation of the p23 protein content in normal, untransformed human bronchial/tracheal epithelial cells to 48% of its content also suppresses the AHR protein levels to 54% of its content. This p23-mediated suppression of AHR is responsible for the repression of …

Multicellular Spheroids Of A549 And A549-Irfp As An In Vitro Model Of Lung Cancer, Xinyu Pei

University of the Pacific Theses and Dissertations

Lung cancer is the second most common cancer in both men and women around the world, and 85% of it is non-small cell lung cancer (NSCLC). It is estimated that in 2020, there will be 228,820 cases of lung cancer and 135,720 deaths from lung (American Cancer Society, 2020). The prognosis of lung cancer is poor (

Traditionally, the most commonly used in vitro method for screening therapeutic drugs is monolayer cell cultures, which are reproducible, convenient and of low cost. However, monolayer cell culture models are unable to reproduce many properties of in vivo solid tumors such as the …

Role Of Polymer Physicochemical Properties On In Vitro Mucoadhesion, Qing Zhang

University of the Pacific Theses and Dissertations

Polymers with mucoadhesive properties are universally used in the development of mucoadhesive drug delivery system. Their physicochemical properties as well as the mechanisms related to their adhesive actions draw great attention for the modification of mucoadhesive properties.

In this study, relationships between physicochemical properties of hydroxypropyl methylcellulose (HPMC) compacts and mucoadhesive performance were investigated. Different commercial grades of HPMC (K3, E3, E5, E50, K4M, E4M and K15M) were prepared into compacts, and their surface hydrophilicity and hydration behavior were characterized. The in vitro mucoadhesive performance was determined by the tension strength between the compacts and different regions of mucous membrane …

Effects Of Chronic Energy Drink Consumption On Cardiometabolic Endpoints, May Chen

University of the Pacific Theses and Dissertations

Background: Since its introduction in the early 2000s, energy drinks have become increasingly popular among an extensive range of consumers, including adolescents and young adults. Currently, the United States Food and Drug Administration (FDA) does not regulate the formulation of energy drinks, which may vary widely in the amounts of caffeine and sugar, as well as various types of supplements. Recent reports of severe and fatal adverse effects related to energy drinks have led to growing concerns on the safety of energy drink consumption.

Objective: This study aimed to investigate the effects of chronic daily consumption of energy drinks on …

Midazole-Based Ph-Sensitive Convertible Liposomes For Anticancer Drug Delivery, Ruiqi Huang

University of the Pacific Theses and Dissertations

Solid tumors possess biological features that are different from those in healthy tissues, which provides opportunities of anticancer treatment by nanomedicines. Due to the presence of the fenestrated tumor vasculatures, nanomedicines can selectively accumulate in tumor tissues by the enhanced permeability and retention (EPR) effect. The acidic pH in tumor interstitium (pH 6.0-7.0) also provides a promising mechanism to trigger the nanomedicines to promote the cellular uptake of cargo drugs. The previously reported stealth liposomes coated with PEG are known to accumulate in tumors owing to their prolonged circulation time. The PEG coating on liposomes can hinder serum protein adsorption …

Studies On The Size And Non-Planarity Of Aromatic Stacking Moiety On Conformation Selectivity And Thermal Stabilization Of G-Quadruplexes, Mandeep Singh

University of the Pacific Theses and Dissertations

Targeting DNA has the advantage over proteins for cancer remediation because of the fewer copies of the ligands required for the desired therapeutic effect. Traditionally, covalent DNA binders like alkylating agents have been used to induce genetic instability through the formation of DNA lesions and strand breaks, leading to cellular apoptosis. The primary drawback of this treatment is the non-specific binding that affects both cancerous and non-cancerous cells. G-quadruplexes are the DNA secondary structures that are present in abundance near the promoter regions of the oncogenes and are involved in the regulation of their activities. A ligand-mediated stabilization of G-quadruplexes …