Medical Toxicology Commons^™

Nf-Κb-Mediated Oxidative Stress Drives Cigarette Smoke-Induced Emt In Human Bronchial Cells, Sarah M. Alqithami

Theses and Dissertations--Toxicology and Cancer Biology

Cigarette smoke contains over 7,000 chemicals, many being carcinogens and proinflammatory agents contributing to chronic respiratory diseases like COPD and lung cancer. This study investigated responses of human bronchial epithelial cells (HBECs) to cigarette smoke condensate (CSC), focusing on oxidative stress and NF-κB signaling. Three HBEC lines were exposed to non-cytotoxic CSC doses for 48 hours, inducing morphological changes consistent with epithelial-to-mesenchymal transition (EMT). RNA sequencing revealed transcriptomic shifts in all cell lines, particularly affecting genes related to oxidative stress, inflammation, hypoxia, and metabolism. Enrichment analyses confirmed activation of NRF2 antioxidant, NF-κB and IL-17 inflammatory, and hypoxiainducible factor pathways, indicating …

Elucidating The Adverse Effects Of Chronic Pfos Exposure On Gastrointestinal Pathology And Colorectal Cancer, Jerika Durham

Theses and Dissertations--Toxicology and Cancer Biology

Commonly referred to as "forever chemicals," per- and polyfluoroalkyl substances (PFAS) have been linked to a number of detrimental health effects, including an elevated risk of cancer. One "long-chain" subtype of PFAS, perfluorooctanesulfonic acid (PFOS), has a long elimination half-life and a significant propensity for bioaccumulation. Because PFOS is commonly found in drinking water, the gastrointestinal system absorbs it at a high rate. Recent studies demonstrate that PFAS exposures promote intestinal inflammation and gut barrier dysfunction. However, how a long-term PFOS exposure affects colorectal cancer (CRC) progression is not known. Therefore, the purpose of this research is to understand how …

Investigating Plk1 In Pulmonary Fibrosis, Tempany Arbogast

Theses and Dissertations--Toxicology and Cancer Biology

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal interstitial lung disease, with a median survival of only 2–3 years following diagnosis. In the United States, the disease contributes to more than 40,000 deaths annually, underscoring its severe clinical burden. Alveolar type II (AT2) lung epithelial cells serve as progenitors that maintain alveolar integrity by replenishing epithelial populations and producing surfactants, while fibroblasts and myofibroblasts regulate the extracellular matrix and structural support. In pulmonary fibrosis (PF) injury to AT2 cells promotes cytokine and growth factor release, driving inflammation, fibroblast proliferation, myofibroblast accumulation, and excessive extracellular matrix deposition. Aberrant AT2 cell …

The Role Of Neural Precursor Cell Expressed Developmentally Down-Regulated Protein 9 In Enhanced Aggressiveness Of Hexavalent Chromium Transformed Bronchial Epithelial Cells, Peter Van Wie

Theses and Dissertations--Toxicology and Cancer Biology

Hexavalent chromium (Cr(VI)) is classified as a confirmed human carcinogen by the International Agency for Research and Cancer (IARC) and by the U.S. Environmental Protection Agency (EPA). Chronic exposure to (Cr(VI)) causes malignant cell transformation in human bronchial epithelial BEAS-2B cells. These Cr(VI)-transformed cells exhibit a highly aggressive phenotype including increased migration, invasion, and angiogenesis. The Cas family protein neuronal precursor developmentally down regulated protein 9 (NEDD9/Cas-L/HEF1) was dramatically overexpressed in Cr(VI)-transformed cells compared to normal BEAS-2B cells. Knockdown of NEDD9 by its shRNA reduced migration and invasion in vitro measured by migration and invasion assays. shNEDD9 reduced tumor formation …

Role Of Oxidized Extracellular Vesicles As Early Biomarkers And Inflammatory Mediators In Chemotherapy-Induced Normal Tissue Injury, Chontida Yarana

Theses and Dissertations--Toxicology and Cancer Biology

Significant advances in the efficacy of cancer therapy have been accompanied by an escalation of side effects that result from therapy-induced injury to normal tissues. Patients with high grade cancer or metastasis are often treated with chemotherapy, 50% of which are associated with reactive oxygen species generation and cellular oxidative stress. Heart is the normal tissue most susceptible to chemotherapy-induced oxidative stress and heart disease is the most common leading cause of death in cancer survivors. However, early and sensitive biomarkers to identify heart disease are still lacking. Extracellular vesicles (EVs) are released from cells during oxidative stress and send …

An Optimized Solid-Phase Reduction And Capture Strategy For The Study Of Reversibly-Oxidized Cysteines And Its Application To Metal Toxicity, John Andrew Hitron

Theses and Dissertations--Toxicology and Cancer Biology

The reversible oxidation of cysteine by reactive oxygen species (ROS) is both a mechanism for cellular protein signaling as well as a cause of cellular injury and death through the generation of oxidative stress. The study of cysteine oxidation is complicated by the methodology currently available to isolate and enrich oxidized-cysteine containing proteins. We sought to simplify this process by reducing the time needed to process samples and reducing sample loss and contamination risk.

We accomplished this by eliminating precipitation steps needed for the protocol by (a) introducing an in-solution NEM-quenching step prior to reduction and (b) replacing soluble dithiothreitol …

Nucleotide Excision Repair: Impacts Of Environmental Carcinogens And Its Role In Cancer Susceptibility In Appalachian Kentucky, Nathaniel C. Holcomb

Theses and Dissertations--Toxicology and Cancer Biology

Lung cancer is a particularly devastating disease, accounting for the most deaths among all cancer types in the United States. Despite a reduction in the country’s smoking rates, cigarette smoking remains the number one risk factor for lung cancer. Additionally arsenic exposure, which occurs primarily through contaminated drinking water in the U.S., is associated with increased lung cancer incidence. The nucleotide excision repair (NER) pathway is critical for maintenance of genomic fidelity, removing DNA lesions that could otherwise promote DNA mutations and drive carcinogenesis. Tobacco smoking introduces significant amounts of DNA damage and produces characteristic DNA mutations found in lung …

Role Of Sulfiredoxin Interacting Proteins In Lung Cancer Development, Hedy Chawsheen

Theses and Dissertations--Toxicology and Cancer Biology

Sulfiredoxin (Srx) is an antioxidant enzyme that can be induced by oxidative stress. It promotes oncogenic phenotypes of cell proliferation, colony formation, migration, and metastasis in lung, skin and colon cancers. Srx reduces the overoxidation of 2-cysteine peroxiredoxins in cells, in addition to its role of removing glutathione modification from several proteins. In this study, I explored additional physiological functions of Srx in lung cancer through studying its interacting proteins. Protein disulfide isomerase (PDI) family members, thioredoxin domain containing protein 5 (TXNDC5) and protein disulfide isomerase family A member 6 (PDIA6), were detected to interact with Srx. Therefore, I proposed …

Loss Of Multidrug Resistance-Associated Protein 1 (Mrp1/Abcc1) Potentiates Doxorubicin-Induced Cardiotoxicity In Mice, Wei Zhang

Theses and Dissertations--Toxicology and Cancer Biology

Doxorubicin (DOX) is a broad-spectrum and effective chemotherapeutic agent, but its use in oncologic practice is limited by dose-dependent cumulative cardiotoxicity. DOX-induced cardiotoxicity is in large part due to its ability to cause oxidative stress. Multidrug resistance associated protein 1 (MRP1/ABCC1) is a member of the ATP-binding cassette (ABC) transporter superfamily. By effluxing a wide variety of endogenous and exogenous substrates, Mrp1 plays important physiological roles in multiple tissues and also protects normal tissues against toxicants. However, the role of MRP1 in heart is largely unknown.

The role of Mrp1 in DOX-induced cardiotoxicity was investigated in Mrp1 null (Mrp1-/-) and …

Effects Of Cellular Heterogeneity And Immune Cells In Angiotensin Ii-Infused Hemorrhaged Ascending Aortas, Kyung Sik Jung

Theses and Dissertations--Toxicology and Cancer Biology

A previous thoracic aortic aneurysm time course study from our laboratory determined that ascending aortic dilation was significantly increased by day 5, and reached a plateau by day 28 of angiotensin II (AngII) infusion. We also found that mice had hemorrhage localized to the ascending aortas by day 5 of AngII infusion. The purpose of these studies was to provide mechanistic insight into the development of AngII-induced ascending aortic hemorrhage.

Male C57BL/6 mice fed normal diet were subcutaneously infused with either AngII (1000 ng/kg/min) or saline for 5 days. To examine cellular heterogeneity, hemorrhaged ascending aortas were collected and sectioned …

Mnsod And Autophagy In Prevention Of Oxidative Mitochondrial Injuries Induced By Uvb In Murine Skin, Vasudevan Bakthavatchalu

Theses and Dissertations--Toxicology and Cancer Biology

UVB radiation is a known environmental carcinogen that causes DNA damage and increase ROS generation in mitochondria. Accumulating evidence suggests that mtDNA damage and increased ROS generation trigger mitochondrial translocation of p53. Within mitochondria, p53 interacts with nucleoid macromolecular complexes such as mitochondrial antioxidant MnSOD, mitochondrial DNA polymerase Polγ, and mtDNA. Mitochondria are considered to be a potential source for damage-associated molecular patterns (DAMPs) such as mtDNA, cytochrome C, ATP, and formyl peptides. Intracytoplasmic release of DAMPs can trigger inflammasome formation and programmed cell death processes. Autophagic clearance of mitochondria with compromised integrity can inhibit inflammatory and cell death processes. …

Novel Mechanism Leading To Mismatch Repair Deficiency And Mutator Phenotype, Janice Ortega Rodríguez

Theses and Dissertations--Toxicology and Cancer Biology

DNA mismatch repair (MMR) is a critical genome-maintenance system. It ensures genome stability by correcting mismatches generated during DNA replication, suppressing homologous recombination, and inducing apoptosis in response to severe DNA damage. As a result, defects in MMR lead to genome-wide mutations and susceptibility to both hereditary and sporadic cancer syndromes. The hallmark of cancer cells defective in MMR is their ability to display frequent instability in simple repetitive DNA sequences, a phenomenon called microsatellite instability (MSI). However, only ~70% of the MSI-positive tumors have identifiable MMR gene mutations, indicating that additional factor(s) are responsible for the MSI phenotype in …

Physiological And Toxicological Roles Of Abc Transporters In Cellular Efflux Of Substrates, Donna J. Coy

Theses and Dissertations--Toxicology and Cancer Biology

ATP-binding cassette (ABC) transporters are transmembrane proteins that transport a wide variety of substrates across intra and extra-cellular membranes. A few examples of endo and xenobiotic substrates are metabolic products, lipids, sterols, and drugs. An important function of ABC transporters involved in export is to prevent intracellular the buildup of toxic products. Several ABC transporters have also been associated with drug resistance upon treatment with chemotherapeutic agents. P-glycoprotein (P-GP) and the multidrug resistant (MRP) transporters of the ABC C family are examples of transporters that confer chemo-resistance.

We have studied two unique roles of ABC transporters in the liver and …