Medicine and Health Sciences Commons^™

Characterizing The Combination Of Rpa Inhibitors With Parp Inhibitors In High-Grade Serous Ovarian Cancer, Yat Tang

Theses & Dissertations

High-grade serous ovarian cancer (HGSC) is the most common and deadly gynecologic malignancy. HGSC patients with BRCA1/2 mutations have homologous recombination deficiency (HRD), requiring parallel pathways to maintain genome integrity (e.g., PARP1, PARP2). Approximately 50% of ovarian carcinomas are estimated to exhibit HRD. For the remaining 50% and the large percentage of HRD patients with acquired or innate resistance to single-agent PARP inhibitors, there is a need to develop alternative therapeutic strategies.

Replication Protein A (RPA) is a heterotrimeric protein crucial for genome maintenance. Phosphorylation of RPA in DNA damage response (DDR) is a negative regulator of DNA end resection. …

Theranostics For Antiretroviral Biodistribution And Pharmacokinetics, Brendan M. Ottemann

Theses & Dissertations

RATIONALE: Our laboratories birthed the field of human immunodeficiency virus (HIV) theranostics. The new field allows simultaneous detection (diagnostics) and treatment (therapeutic) for the identification, treatment and inevitable elimination of virus in cell and tissue compartments. By employing theranostics, antiretroviral drugs (ARVs) can be tracked in lymph nodes, gut, spleen and liver. Cellular viral reservoirs including CD4+ T cell populations and mononuclear phagocytes (MP; monocytes, macrophages, microglia and dendritic cells) along with subcellular endosomal structures can now be targeted for drug delivery bringing therapeutics to areas where virus replicates. The overarching idea rests in improving precision targeted ARV delivery. …

Hiv-1 Elimination In Humanized Mice, Hang Su

Theses & Dissertations

Human immunodeficiency virus type one (HIV-1) exclusively infects humans and chimpanzees. Therefore, animal models are required for all investigations of viral pathogenesis, therapy and cure. Immunodeficient mice transplanted with human hematopoietic stem cells, termed humanized mice, support the development of multiple human cell lineages throughout the cell’s life span. To this end, we used humanized mice to evaluate the dynamic changes of host immunologic and viral profiles during both acute and chronic HIV-1 infection. We identified the temporal and spatial distribution of HIV-1 cell and tissue compartment infections and outlined correlations made between viral progression and host immunity by comparing …

Defining The Role Of Tyrosine Phosphorylation In The Regulation Of Connexin43 In Cardiac Diseases, Li Zheng

Theses & Dissertations

Connexins are integral membrane proteins that oligomerize to form gap junction channels. Ions and small molecules diffuse intercellularly through these channels, allowing individual cellular events to synchronize into the functional response of an entire organ. Gap junction channels composed of Connexin43 (Cx43) mediate electrical coupling and impulse propagation in the normal working myocardium. In the failing heart, Cx43 remodeling (decreased expression, altered phosphorylation state, loss at intercalated discs, and increased presence at lateral membranes) contributes to rhythm disturbances and contractile dysfunction. While there is considerable information regarding key interactions of Cx43 in the regulation of gap junction channels, unfortunately, the …

Delivery Of Small Molecule And Rna Using Synthetic Polymeric Micelles And Multifunctional Exosomes For The Treatment Of Type 1 Diabetes, Yang Peng

Theses & Dissertations

Type 1 diabetes is one of the most challenging chronic autoimmune diseases. The destruction and dysfunction of insulin-secreting β cells are the results of inflammatory infiltration and the synergistic effect of multiple immune cells. The aim of this dissertation is to develop novel and reliable therapeutic approaches to advance the treatment of T1D: including chemical modification of a broad-spectrum immunosuppressant, co-application of small molecule based immune intervention and siRNA based β cell preservative therapy, and administration of a PI3K-δ/γ dual inhibitor to specifically target immune cells, utilizing synthetic polymeric micelles or natural produced multi-functional exosomes derived from human bone marrow …

The Role Of Histone Chaperone Fact Complex In Base Excision Repair Pathway And Its Therapeutic Potential In Colon Cancer And Medulloblastoma, Heyu Song

Theses & Dissertations

Base excision repair (BER) pathway is required for the removal of damaged bases caused by alkylation, oxidation and ring-saturation. Human apurinic/apyrimidinic endonuclease 1 (APE1) plays a central role in BER pathway. Although repair of damaged bases by recombinant APE1 has been well investigated in vitro, how APE1 gains access to damaged bases in the context of chromatin is largely unknown. A prominent member of the histone chaperone family, FACT (Facilitates Chromatin Transcription) is thought to reorganize nucleosomes through the destabilization of multiple intra-nucleosome contacts. FACT complex is composed of two polypeptides identified as SPT16 (Suppressor of Ty 16) and SSRP1 …

Synthesis And Characterization Of Long Acting Darunavir Prodrugs, Mary Banoub

Theses & Dissertations

Patient adherence is critical for ART success to ensure adequate viral suppression, therefore, long-acting antiretrovirals are soon replacing current daily regimens. In recent years, two drugs were successfully transformed into long-acting injectables; CAB LA and RPV LA. These long-acting nanoformulations made it possible to abandon the daily pill burden, instead approximately a bimonthly injection of both drugs is enough to suppress and maintain viral load suppression. Our laboratory has been instrumental in transforming FDA-approved and experimental-HIV medications into long-acting slow effective release drugs, also known as LASER ART. LASER ART consists of slow drug metabolism and high permeability and retention …

Targeted Inhibition Of Histone Deacetyltransferases For Pancreatic Cancer Therapy, Richard Laschanzky

Theses & Dissertations

Pancreatic ductal adenocarcinoma (PDAC) is a deadly disease with a dismal five-year survival rate of less than 10%. One major obstacle in PDAC treatment is acquired drug resistance. Pan-histone deacetylase inhibitors (pan-HDACi) are a relatively new class of anti-cancer drugs, with demonstrated ability to overcome drug resistance and re-sensitize PDAC tumors to Gemcitabine (Gem). These agents target HDACs, a family of 18 enzymes (divided into four classes, I-IV) that catalyze the deacetylation of histones and other cellular proteins and have multiple effects on cell growth, differentiation, survival, and tumorigenesis. Although pan-HDACi have shown significant efficacy in preclinical analysis, and some …

Long Term Outcomes Of Surgical And Clinical Symptoms Following Minimally Invasive Heller Myotomy: A Retrospective Clinical Database Review, Laura E. Flores, Priscila Rodrigues Armijo, Bhavani Pokala, Sarah Samreen, Dmitry Oleynikov

Graduate Medical Education Research Journal

I

Introduction

Minimally invasive Heller myotomy rates have increased, but little evidence is available regarding long term clinical and surgical outcomes. Our aim was to evaluate long term symptom improvement and medication resolution for patients undergoing minimally invasive Heller myotomy.

Methods

A single-institution database was retrospectively reviewed for patients undergoing laparoscopic Heller myotomy (LHM) or robotic Heller myotomy (RHM) during 2007-2018. Patients with primary HM followed by a Dor fundoplication were included. Demographics and surgical data were analyzed. Esophageal symptoms, testing, and medication use were collected preoperatively (pre-op), at 6-month (6-mo), 12-month (12-mo), and long-term (LT; 12-mo+) follow-up. Analysis was …

Association Between Gastroduodenal Ulcer And Age Of Diagnosis Of Head And Neck, Gastroduodenal And Pancreatic Cancer, Rukevwe Madusor

Capstone Experience

Background: Cancer is the second leading cause of death in the United States and remains a major public health problem worldwide. Epidemiological studies have demonstrated that insulin like growth factor-1 (IGF-1) is linked to ulcers and most cancers. Although studies have investigated the role of IGF1 in ulcer healing and cancer pathogenesis, the link between ulcer and cancer remains unclear. Hence, we assessed the relationship between ulcers and cancers.

Methods: This study consists of a sample of 180 cancer patients obtain by convenience sampling who were seen at Nebraska Medicine and were enrolled in the integrated cancer repository for cancer …

Macromolecular Prodrug For The Treatment Of Ulcerative Colitis, Yuanyuan Sun

Theses & Dissertations

Ulcerative colitis is a chronic inflammatory bowel disease affecting the colon. More than 1 million Americans are affected, with the annual economic burden up to 14.9 billion in the United States. By far, ulcerative colitis still lacks the cure and the current treatment strategies are limited due to severe side effects and in-sufficient efficacy. The tofacitinib (Xeljanz) is the only approved oral medication by for adults with moderately-to-severely-active ulcerative colitis. But the related side effects and serious infections still have to be resolved. In the previous study in our lab, the researchers have successfully developed and characterized multiple hy-drophilic prodrug …

Synthesis And Characterization Of Long-Acting Rilpivirine Prodrugs, James R. Hilaire

Theses & Dissertations

Antiretroviral therapy (ART) requires lifelong daily dosing to suppress viral replication, restore or maintain immune function and improve quality of life. As an alternative, long-acting (LA) antiretrovirals (ARVs) aim to deliver therapeutic drug concentrations over an extended period, ultimately requiring monthly or even more extended dosing intervals. Specifically, the success of recent clinical trials examining LA cabotegravir and rilpivirine (CAB and RPV LA) highlight the advent of these novel HIV-1 therapeutics. Further optimization of LA dosage forms are required and rests upon improving dosing frequency, injection volumes and tissue distribution to viral compartments. To this end, we report the synthesis …

Evaluation Of The Role Of Microvascular Pathology On Peripheral Artery Disease, Constance Mietus

Theses & Dissertations

Background: Peripheral Artery Disease (PAD) begins with atherosclerotic narrowing of arteries, including those that supply the legs. Individuals with PAD experience pain during walking, which becomes increasingly limiting. Studies from our group and others have shown that a myopathy is present in the skeletal muscle of PAD patients, and is characterized by myofiber degeneration, fibrosis, and remodeling of vessels ranging from 50 – 150 mm in diameter. However, microvascular pathology, particularly of the smallest microvessels (5 – 15 mm in diameter) remains poorly characterized. Furthermore, little is known about the relationships between microvascular architecture, microperfusion, and patient walking performance. We …

Role Of Rac1-Pak Pathway In Aggressive B-Cell Lymphoma, Tian Tian

Theses & Dissertations

Aggressive B-cell lymphomas are diverse group of neoplasms that arise at different stages of B-cell development and by various mechanisms of neoplastic transformation. Aggressive B-cell lymphomas include many types, subtypes and variants of diffuse large B-cell lymphoma (DLBCL), Burkitt lymphoma (BL), mantle cell lymphoma (MCL) and B lymphoblastic lymphoma. The treatment of patients with aggressive B-cell lymphomas remains a clinical challenge. Conventional chemotherapeutic regimens, mainly based on the CHOP (cyclophosphamide, hydroxydaunorubicin, oncovin and prednisone) combination, obtain a relatively high number of complete or partial clinical responses (20-80%), but the tumor relapses in most patients, who will die of the disease. …

The Role Of Ros In The Progression And Treatment Of Castration-Resistant Prostate Cancer, Dannah R. Miller

Theses & Dissertations

Prostate cancer is the second leading cause of cancer-related deaths in U.S. men, primarily due to the development of castration-resistant (CR) prostate cancer (PCa), of which there are no effective treatment options. Reactive oxygen species (ROS) plays a critical role in prostate carcinogenesis, including the progression of the CR PCa phenotype. ROS regulates both cell proliferation and apoptosis; a moderate increase in ROS can promote proliferation; however, a substantial rise in ROS levels will result in apoptosis. Oxidase p66Shc is elevated in clinical PCa cells and has been associated with a metastatic phenotype of CR PCa cells, promoting PCa cell …

Development Of A Long-Acting Nanoformulation Of Dolutegravir For Prevention And Treatment Of Hiv-1 Infection, Brady Sillman

Theses & Dissertations

Dolutegravir (DTG) is a potent human immunodeficiency virus type 1 (HIV-1) integrase strand-transfer inhibitor (INSTI) with a high barrier to viral drug resistance. However, opportunities to improve its profile abound. These include extending the drug’s apparent half-life, increasing penetrance to “putative” viral reservoirs, and reducing inherent toxicities. These highlight, in part, the need for long-acting, slow effective release antiretroviral therapy (LASER ART) delivery schemes. A long-acting (LA) DTG was made by synthesizing a hydrophobic and lipophilic prodrug encased with poloxamer (P407) surfactant. This modified DTG (MDTG) reduced systemic metabolism and polarity, increased lipophilicity and membrane permeability, improved encapsulation, and formed …

Initiation Of A Roundtable Meeting To Determine Safety Hazards And Provide Education To Range Bison Herd Workers, Lucia Finocchiaro

Capstone Experience

This capstone project serves as an important piece of greater project studying bison handling. Bison production is both a growing and dangerous industry. As a new enterprise in many parts of the country and on tribal lands, significant numbers of untrained employees may be hired. This project undertakes methods to better understand the risks associated with bison handling and to thereby improve handling procedures and increase safety. Herd managers (from tribal and non-tribal sites), researchers, safety experts, and stakeholders were brought together for a roundtable meeting in Omaha. This meeting was designed to provide stakeholders a forum to discuss common …

The Mitochondrial Deoxyguanosine Kinase Is Required For Cancer Cell Stemness In Lung Adenocarcinoma, Shengchen Lin, Chongbiao Huang, Jianwei Sun, Oana Bollt, Xiuchao Wang, Eric Martine, Jiaxin Kang, Matthew D. Taylor, Bin Fang, Pankaj K. Singh, John Koomen, Jihui Hao, Shengyu Yang

Journal Articles: Eppley Institute

The mitochondrial deoxynucleotide triphosphate (dNTP) is maintained by the mitochondrial deoxynucleoside salvage pathway and dedicated for the mtDNA homeostasis, and the mitochondrial deoxyguanosine kinase (DGUOK) is a rate-limiting enzyme in this pathway. Here, we investigated the role of the DGUOK in the self-renewal of lung cancer stem-like cells (CSC). Our data support that DGUOK overexpression strongly correlates with cancer progression and patient survival. The depletion of DGUOK robustly inhibited lung adenocarcinoma tumor growth, metastasis, and CSC self-renewal. Mechanistically, DGUOK is required for the biogenesis of respiratory complex I and mitochondrial OXPHOS, which in turn regulates CSC self-renewal through AMPK-YAP1 signaling. …

Mitochondrial Superoxide Disrupts The Metabolic And Epigenetic Landscape Of Cd4, Cassandra M. Moshfegh, Christopher W. Collins, Venugopal Gunda, A. Vasanthakumar, J. Z. Cao, Pankaj K. Singh, L. A. Godley, Adam J. Case

Journal Articles: Eppley Institute

While the role of mitochondrial metabolism in controlling T-lymphocyte activation and function is becoming more clear, the specifics of how mitochondrial redox signaling contributes to T-lymphocyte regulation remains elusive. Here, we examined the global effects of elevated mitochondrial superoxide (O₂^-) on T-lymphocyte activation using a novel model of inducible manganese superoxide dismutase (MnSOD) knock-out. Loss of MnSOD led to specific increases in mitochondrial O₂^- with no evident changes in hydrogen peroxide (H₂O₂), peroxynitrite (ONOO^-), or copper/zinc superoxide dismutase (CuZnSOD) levels. Unexpectedly, both mitochondrial and glycolytic metabolism showed significant reductions …

Selective Inhibition Of Histone Deacetylases 1/2/6 In Combination With Gemcitabine: A Promising Combination For Pancreatic Cancer Therapy, Richard S. Laschanzky, Lisa E. Humphrey, Jihyun Ma, Lynette M. Smith, Thomas J. Enke, Surendra K. Shukla, Aneesha Dasgupta, Pankaj K. Singh, Gillian M. Howell, Michael G. Brattain, Quan P. Ly, Adrian R. Black, Jennifer D. Black

Journal Articles: Eppley Institute

Pancreatic ductal adenocarcinoma (PDAC) has a five-year survival rate of <10% due in part to a lack of effective therapies. Pan-histone deacetylase (HDAC) inhibitors have shown preclinical efficacy against PDAC but have failed in the clinic due to toxicity. Selective HDAC inhibitors may reduce toxicity while retaining therapeutic efficacy. However, their use requires identification of the specific HDACs that mediate the therapeutic effects of HDAC inhibitors in PDAC. We determined that the HDAC1/2/3 inhibitor Mocetinostat synergizes with the HDAC4/5/6 inhibitor LMK-235 in a panel of PDAC cell lines. Furthermore, while neither drug alone synergizes with gemcitabine, the combination of Mocetinostat, LMK-235, and gemcitabine showed strong synergy. Using small interfering (si)RNA-mediated knockdown, this synergy was attributed to inhibition of HDACs 1, 2, and 6. Pharmacological inhibition of HDACs 1 and 2 with Romidepsin and HDAC6 with ACY-1215 also potently synergized with gemcitabine in a panel of PDAC cell lines, and this drug combination potentiated the antitumor effects of gemcitabine against PDAC xenografts in vivo. Collectively, our data show that inhibition of multiple HDACs is required for therapeutic effects of HDAC inhibitors and support the development of novel strategies to inhibit HDACs 1, 2, and 6 for PDAC therapy.

Fascin Controls Metastatic Colonization And Mitochondrial Oxidative Phosphorylation By Remodeling Mitochondrial Actin Filaments, Shengchen Lin, Chongbiao Huang, Venugopal Gunda, Jianwei Sun, Srikumar P. Chellappan, Zengxun Li, Victoria Izumi, Bin Fang, John Koomen, Pankaj K. Singh, Jihui Hao, Shengyu Yang

Journal Articles: Eppley Institute

The deregulation of the actin cytoskeleton has been extensively studied in metastatic dissemination. However, the post-dissemination role of the actin cytoskeleton dysregulation is poorly understood. Here, we report that fascin, an actin-bundling protein, promotes lung cancer metastatic colonization by augmenting metabolic stress resistance and mitochondrial oxidative phosphorylation (OXPHOS). Fascin is directly recruited to mitochondria under metabolic stress to stabilize mitochondrial actin filaments (mtF-actin). Using unbiased metabolomics and proteomics approaches, we discovered that fascin-mediated mtF-actin remodeling promotes mitochondrial OXPHOS by increasing the biogenesis of respiratory Complex I. Mechanistically, fascin and mtF-actin control the homeostasis of mtDNA to promote mitochondrial OXPHOS. The …

Human Islet Response To Selected Type 1 Diabetes-Associated Bacteria: A Transcriptome-Based Study, Ahmed M. Abdellatif, Heather Jensen Smith, Robert Z. Harms, Nora Sarvetnick

Journal Articles: Eppley Institute

Type 1 diabetes (T1D) is a chronic autoimmune disease that results from destruction of pancreatic β-cells. T1D subjects were recently shown to harbor distinct intestinal microbiome profiles. Based on these findings, the role of gut bacteria in T1D is being intensively investigated. The mechanism connecting intestinal microbial homeostasis with the development of T1D is unknown. Specific gut bacteria such as Bacteroides dorei (BD) and Ruminococcus gnavus (RG) show markedly increased abundance prior to the development of autoimmunity. One hypothesis is that these bacteria might traverse the damaged gut barrier, and their constituents elicit a response from human islets that causes …

Metabolic Alterations In Pancreatic Cancer Progression, Enza Vernucci, Jaime Abrego, Venugopal Gunda, Surendra K. Shukla, Aneesha Dasgupta, Vikrant Rai, Nina V. Chaika, Kyla Buettner, Alysha Illies, Fang Yu, Audrey J. Lazenby, Benjamin J. Swanson, Pankaj K. Singh

Journal Articles: Eppley Institute

Pancreatic cancer is the third leading cause of cancer-related deaths in the USA. Pancreatic tumors are characterized by enhanced glycolytic metabolism promoted by a hypoxic tumor microenvironment and a resultant acidic milieu. The metabolic reprogramming allows cancer cells to survive hostile microenvironments. Through the analysis of the principal metabolic pathways, we identified the specific metabolites that are altered during pancreatic cancer progression in the spontaneous progression (KPC) mouse model. Genetically engineered mice exhibited metabolic alterations during PanINs formation, even before the tumor development. To account for other cells in the tumor microenvironment and to focus on metabolic adaptations concerning tumorigenic …

Inhibition Of Geranylgeranyl Diphosphate Synthase Is A Novel Therapeutic Strategy For Pancreatic Ductal Adenocarcinoma, Staci L. Haney, Michelle L. Varney, Yashpal S. Chhonker, Simon Shin, Kamiya Mehla, Ayrianne J. Crawford, Heather Jensen Smith, Lynette M. Smith, Daryl J. Murry, Michael A. Hollingsworth, Sarah A. Holstein

Journal Articles: Eppley Institute

Rab proteins play an essential role in regulating intracellular membrane trafficking processes. Rab activity is dependent upon geranylgeranylation, a post-translational modification that involves the addition of 20-carbon isoprenoid chains via the enzyme geranylgeranyl transferase (GGTase) II. We have focused on the development of inhibitors against geranylgeranyl diphosphate synthase (GGDPS), which generates the isoprenoid donor (GGPP), as anti-Rab agents. Pancreatic ductal adenocarcinoma (PDAC) is characterized by abnormal mucin production and these mucins play important roles in tumor development, metastasis and chemo-resistance. We hypothesized that GGDPS inhibitor (GGDPSi) treatment would induce PDAC cell death by disrupting mucin trafficking, thereby inducing the unfolded …