Cancer Biology Commons^™

Investigation Of Genx Exposure To Pathways Associated With Colorectal Cancer Risk, Emily J. Ferguson

Theses and Dissertations--Toxicology and Cancer Biology

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants widely detected in drinking water and food sources, resulting in chronic human exposure. Among these compounds, hexafluoropropylene oxide dimer acid (HFPO-DA), commonly known as GenX, has been introduced as a short-chain replacement for legacy PFAS such as perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA). Although GenX is believed to be a safer alternative, emerging research suggests it can still affect human health.

Colorectal cancer (CRC) is the third most commonly diagnosed cancer and the second leading cause of cancer-related death in the United States, highlighting the need to better understand environmental …

Uncovering The Mechanism Of Reep2-Mediated Emt-Driven Membrane Trafficking In Lung Adenocarcinoma, Kevin Fulp

Theses and Dissertations--Toxicology and Cancer Biology

Membrane trafficking is frequently disrupted during cancer progression, and the underlying mechanisms remain largely unknown. Currently, no effective drugs target dysregulated membrane trafficking for cancer treatment. Recent evidence has demonstrated that epithelial-to-mesenchymal transition (EMT) in lung adenocarcinoma (LUAD) employs a membrane trafficking program to coordinate cancer cell invasion and immunosuppression. To further dissect the pro-tumorigenic membrane trafficking program, we initiated an in vivo CRISPRi screen to assess more than 2,000 membrane trafficking-related genes in a syngeneic mouse LUAD model. We identified REEP2, an endoplasmic reticulum (ER) shaping protein, as a novel regulator of EMT-driven membrane trafficking. High REEP2 expression is …

Reep2-Driven Pro-Metastatic Secretion Promotes Lung Cancer Progression, Oluwafunminiyi E. Obaleye

Theses and Dissertations--Toxicology and Cancer Biology

Membrane trafficking plays a critical role in cellular function and is frequently dysregulated in cancer to promote metastasis. In lung adenocarcinoma (LUAD), the epithelial-to-mesenchymal transition (EMT) activating transcription factor, ZEB1, drives a pro-metastatic membrane trafficking program; however, the underlying molecular mechanisms remain poorly understood. Using a CRISPR interference (CRISPRi) in vivo screen of 2,099 membrane trafficking regulators in a syngeneic mouse model of EMT-driven LUAD, we identified REEP2 — an endoplasmic reticulum (ER) shaping protein — as a critical regulator of tumor progression. REEP2 mRNA expression correlates with poor prognosis, EMT signatures, and an immunosuppressive tumor microenvironment in LUAD patients. …

Developing Novel Therapeutic Strategies For Mcrc With A Brafv600e Mutation, Mariah Geisen

Theses and Dissertations--Toxicology and Cancer Biology

Colorectal cancer (CRC) is the second leading cause of cancer death worldwide. The overall incidence rates of CRC have decreased in those over 50, but there is an increasing incidence rate in those under 50. Risk factors for CRC include diet, family history, and a sedentary lifestyle. Early detection of CRC is key to patient survival and treatment response. Localized CRC has a survival rate of 90% and allows for surgical resection and chemotherapy. The 5-year survival for metastatic CRC (mCRC) is significantly reduced to around 14%. Despite early detection, 50% of patients will develop metastasis after surgical resection and …

Elucidation Of Mismatch Repair Regulation By Abl1: Advantages/Disadvantages Of Tyrosine Kinase Inhibitor Treatment, Hannah Daniels

Theses and Dissertations--Toxicology and Cancer Biology

DNA mismatch repair (MMR) is a critical repair process necessary for not only repairing mispairs incorporated into the DNA during replication, but also for inducing apoptosis in response to certain types of DNA damage. MMR is required for maintaining genomic integrity and due to the importance of this pathway, any impairment of its function can lead to increased mutation frequency, which is well known to be a driving force of cancer development, progression, and resistance. Despite extensive studies involving the proteins involved in the MMR pathway, the regulation of those proteins remains relatively unknown. Regulation of MLH1, a protein necessary …

Acquired Treatment Resistance In Prostate Cancer Via The Production Of Radiation Derived Extracellular Vesicles Containing Mitochondrial Proteins, Caitlin Miller

Theses and Dissertations--Toxicology and Cancer Biology

Radiation treatment (RT) is one of the most commonly administered treatments for prostate cancer (PCa) patients, yet the recurrence of tumors after RT remains one of the significant challenges in the eradication of PCa. In addition to induction of DNA damage, ROS production, and cell death, we found that RT promotes Extracellular vesicle (EV) production in PCa cells, at least in part, through H₂O₂ production (Miller CE et al., Antioxidants 2022, PMID 36358489). Since we observed EV production upon RT, EVs and their contents could play a role(s) in cancer survival after RT. By using flow cytometry …

Porcupine’S Role In The Enhancement Of Enzalutamide Efficacy In Drug Resistant Prostate Cancer, Katelyn Jones

Theses and Dissertations--Toxicology and Cancer Biology

Androgen receptor (AR) signaling continues to participate as a vital component of castration-resistant prostate cancer (CRPC). Subsequently, this has led to the development of Androgen Signaling Inhibitors (ASI), specifically Enzalutamide (ENZ), which is a direct inhibitor of AR, to clinically manage CRPC. Inevitably, ENZ treatment only provides improvement for approximately two months before advancing to an incurable form, ENZ-resistant CRPC. With PCa ranking as the second leading cause of cancer-related deaths in USA males, there is an urgency and necessity for the discovery and development of novel therapeutic approaches for CRPC. Wnt signaling has been extensively documented in its involvement …

Therapeutic Approaches And Novel Mechansims In Cancer Progression, Kendall Simpson

Theses and Dissertations--Toxicology and Cancer Biology

Prostate cancer (PCa) remains the most diagnosed cancer among men in the United States. There are various therapeutic routes that are implored to combat this fatal disease, and our work aims to increase the options made available to PCa patients. A combination treatment of Enzalutamide (Enz), an FDA approved drug for castration-resistant PCa patients, and Metformin, an FDA approved drug for type 2 diabetes, was utilized to enhance the efficacy of Enz in Enz-resistant PCa, both in vitro and in vivo. Thymic Lymphoma is one of the most common malignancies that can occur in various tissues and organs. Genomic stability …

Delineating Contributions Of Genotype And Lineage To Lung Cancer Therapy Response, Kassandra Jo Naughton

Theses and Dissertations--Toxicology and Cancer Biology

Non-small cell lung cancer (NSCLC) heterogeneity is a major challenge for determining effective treatment strategies. Adenocarcinomas (ADCs) and squamous cell carcinomas (SCCs) are histologically and epigenetically distinct subtypes of NSCLC. Patients with ADC tumors harboring mutations in both KRAS and LKB1 (aka STK11) have lower survival rates than those with KRAS-only tumors. KRAS/LKB1 tumors are not only aggressive, but also respond poorly to immunotherapy. However, these data are limited to ADCs, and it is unclear if SCCs with this genotype are also resistant to immunotherapy. We developed a mouse model of Kras^mut/Lkb1^mut capable of producing …

Understanding The Role Of Peroxiredoxin Iv In Colorectal Cancer Development, Pratik Thapa

Theses and Dissertations--Toxicology and Cancer Biology

Reactive oxygen species (ROS) are oxygen-containing free radicals and/or molecules that are more reactive than O₂. ROS such as hydroxyl radical (•OH) and hydrogen peroxide (H₂O₂) are produced naturally in the body as a result of reactions such as aerobic respiration and oxidative protein folding. ROS undergo reduction-oxidation (redox) reactions and mediate cell signaling. Accumulation of excessive ROS can damage DNA, RNA, protein and lipids. Antioxidants are enzymes and small molecules that react with ROS to modulate redox signaling and to prevent and repair oxidative damage. Examples of antioxidants include glutathione, thioredoxin, superoxide dismutase, …

Targeting Ezh2 To Improve Outcomes Of Lung Squamous Cell Carcinoma, Tanner Ducote

Theses and Dissertations--Toxicology and Cancer Biology

Only 20% of patients diagnosed with lung squamous cell carcinoma (LSCC) respond to immunotherapy. Anti-PD1 immunotherapy is most commonly prescribed to these patients; however, most will become refractory. It is important to understand the mechanisms underlying this problem to increase durability and survival. Building upon the work of other groups, our lab has demonstrated that the inhibition of the histone methyltransferase, EZH2, is crucial to maintaining an immunologically responsive microenvironment. Based on our data, we hypothesize that combining EZH2 inhibitors with anti-PD1 therapy will increase response and durability. To study non-small cell lung cancers (NSLC) our lab uses a variety …

Conserved Novel Interactions Between Post-Replicative Repair And Mismatch Repair Proteins Have Differential Effects On Dna Repair Pathways, Anna K. Miller

Theses and Dissertations--Toxicology and Cancer Biology

DNA mismatch repair (MMR) is the DNA repair mechanism that repairs base-base mispairs and small insertions and deletions remaining after replication. MMR is also required for apoptosis after certain types of exogenous DNA damage that result in damage-associated mispairs. The basic MMR mechanism is well understood; however, proteins associated with MMR continue to be identified. The roles of these interacting proteins in MMR are largely unknown. We have identified the yeast protein Rad5 as a novel interactor of the critical MMR proteins Msh2 and Mlh1. Rad5 is a DNA helicase and E3 ubiquitin ligase involved in post-replicative repair. However, to …

Elucidating The Functional Importance Of Peroxiredoxin Iv In Prostate Cancer And Its Secretion Mechanism, Na Ding

Theses and Dissertations--Toxicology and Cancer Biology

Prostate cancer is the most common and second leading cause of cancer death in men. Prevailing theories state that inflammation may drive prostate carcinogenesis via oxidative stress and the generation of reactive oxygen species (ROS) that induce somatic mutagenesis. Since high proliferating cells or cancer cells exhibit aberrant metabolism to satisfy the needs of energy for rapid cell proliferation, they also generate high levels of ROS which stimulates the expression of cellular antioxidants to overcome the dysregulation of redox homeostasis through the regulation of redox-sensitive transcription factors. Among different antioxidants, peroxiredoxin (Prx) family proteins are the highly conserved and mostly …

Beyond Mitosis, Plk1-Mediated Phosphorylation Re-Wires Cancer Metabolism And Promotes Cancer Progression, Qiongsi Zhang

Theses and Dissertations--Toxicology and Cancer Biology

Polo-like kinase 1 (PLK1) is a well- characterized regulator of cell division and is known to be highly expressed in certain types of tumors. It has been demonstrated the multifaceted roles of PLK1 in regulation of transcription, translation, epigenetics, DNA damage and cellular metabolism et al. Despite these findings, the precise mechanisms by which PLK1 regulates these processes beyond mitosis remain unclear. PLK1-mediated phosphorylation and misregulation of its substrates has been linked to tumorigenesis, cancer progression, drug resistance and worse prognosis. In this study, we investigated the non-canonical functions of PLK1 in cancer metabolism and drug resistance. We found that …

Extracellular Vesicles And Cancer Therapy: An Insight Into The Role Of Oxidative Stress, Jenni Ho

Theses and Dissertations--Toxicology and Cancer Biology

As a result of improvements in cancer detection and treatment methods, a growing population of cancer survivors are living with side effects associated with their cancer therapy. Oxidative stress plays a significant role in the development of cancer and as a mechanism for cancer therapy to exert its therapeutic effects, resulting in off-target tissue damage. Radiation has been long established as a means to utilize the generation of reactive oxygen species to kill cancer cells, and 50% of chemotherapy agents currently used are associated with inducing oxidative stress. One major side effect observed in cancer survivors is a decline in …

Overcoming Resistance To Sg-Aris In Castration-Resistant Prostate Cancer, Chaohao Li

Theses and Dissertations--Toxicology and Cancer Biology

Prostate cancer (PCa) ranks as the most diagnosed type of cancer and the second leading cause of death in men. Androgen receptor (AR) signaling plays a pivotal function in promoting the survival and progression of PCa. Therefore, medication for PCa mainly focuses on the inhibition of AR pathway, which is termed androgen deprivation therapy (ADT). However, the disease eventually progresses and develops to a lethal stage called castration-resistant prostate cancer (CRPC) that is characterized by resistance to canonical ADT. To deal with this situation, several second-generation AR inhibitors (SG-ARIs) have been created that have better efficacy against AR, including Enzalutamide …

Delineating The Role Of Fatty Acid Metabolism To Improve Therapeutic Strategies For Colorectal Cancer, James Drury

Theses and Dissertations--Toxicology and Cancer Biology

Colorectal cancer (CRC) remains a leading cause of cancer-related deaths in the world, comprising over 1 million new cases each year and over 500,000 deaths. CRC, when detected at an early stage of disease development, can be effectively treated, with a 5-year survival rate of over 90%. Such standard treatments include surgical resection of the primary tumor in combination with adjuvant chemotherapy. However, even with advancements in surgical procedures and chemotherapeutic targets, when CRC progresses to a more advance stage, the 5-year survival rate decreases significantly to just under 14%. This stark decrease in patient survival rate can be directly …

Prostate Cancer Resistance To Cabazitaxel Chemotherapy, Diane Begemann

Theses and Dissertations--Toxicology and Cancer Biology

The plasticity of prostate tumors contributes to the heterogeneity in response and acquisition of therapeutic resistance in advanced prostate cancer. Disruption of the phenotypic landscape via epithelial-mesenchymal transition (EMT) enables prostate tumors to invade and metastasize. Our previous studies demonstrated that cabazitaxel (a 2^nd generation FDA-approved taxane chemotherapy) that is used for treatment of castration-resistant prostate cancer (CRPC), causes reversal of EMT to mesenchymal-epithelial transition (MET). The present study examined the effect of sequencing cabazitaxel chemotherapy mediated MET on prostate tumor re-differentiation and its impact on overcoming resistance in models of advanced prostate cancer.

The presence of DHT (1nM) …

Multivariate Analysis To Identify Potential Biomarkers For Prognosis And Treatment Resistance In Head And Neck Cancer Patients, Christina Ann Wicker

Theses and Dissertations--Toxicology and Cancer Biology

It is estimated that nearly 50,000 individuals in the United States will be diagnosed with head and neck cancer in 2017 (American Cancer Society www.cancer.org). Ninety percent of oral cancers are head and neck squamous cell carcinoma (HNSCC). Major obstacles in the treatment of HNSCC are recurrence and treatment resistance, which contributes to increased mortality. Therefore, there is increased need to determine genetic alterations in HNSCC that may be ideal novel drug targets, and biomarkers to improve diagnostic and prognostic testing.

Abnormal localization and overexpression of base excision repair protein and transcriptional regulator Apurinic/Apyrimidic endonuclease (APE1) has been associated with …

Targeting The Cellular Redox Environment: A Novel Approach For The Treatment Of Hematopoietic Neoplasms, Dustin W. Carroll

Theses and Dissertations--Toxicology and Cancer Biology

Hematopoietic stem cells (HSCs) that function to maintain the hematopoietic compartment through self-renewal and differentiation capacities, as well as their downstream progeny, are susceptible to transformation resulting in the generation of the leukemic stem cell (LSC). Chief in the factors that control HSC regulation and protection of the HSC compartment is the cellular redox environment. Deregulation of the Hematopoietic Stem/Progenitor Cell (HSPC) redox environment results in loss of HSPC function and exhaustion. The characteristic developments of HSPC exhaustion via exposure to redox stress closely mirror phenotypic traits of hematopoietic malignancies, presenting the HSPC/LSC redox environment as a potential therapeutic target. …

Effects Of Chromium On Mouse Splenic T Lymphocytes And Effects Of Ethanol Exposure During Early Neurodevelopment On Behaviors In Mice, Lu Dai

Theses and Dissertations--Toxicology and Cancer Biology

The dissertation consists of three major projects with the focus on the immunotoxicity of chromium and the behavior disorders caused by early ETOH exposure respectively.

Hexavalent chromium [Cr(VI)] is widely used in various industrial processes and has been recognized as a carcinogen. As the first line of host defense system, the immune system can be a primary target of Cr(VI). T cell population represents a major arm of the immune system that plays a critical role in host anti-tumor immunity. Dysfunction of T cells compromises host anti-tumor immunity resulting in oncogenesis. Using mouse splenic T cells as an in vitro …

Overcoming Treatment Resistance In Heterogeneous Tumors, Nikhil Hebbar

Theses and Dissertations--Toxicology and Cancer Biology

Most primary tumors are heterogeneous and are often composed of therapy-sensitive and emerging therapy-resistant cancer cells. Rather unexpectedly, treatment of therapy-sensitive tumor cells in heterogeneous tumor microenvironments resulted in apoptosis of the therapy-resistant cancer cells. We identified a novel Par-4 amino-terminal fragment (PAF, which includes amino acids 1-131 of Par-4) that is produced and released by therapy-sensitive cancer cells following therapy-induced caspase-dependent cleavage of the tumor suppressor Par-4. PAF caused paracrine apoptosis in therapy-resistant cancer cells. Unlike Par-4-inducible apoptosis, which is dependent on the cell surface GRP78 receptor, PAF produced cancer-selective apoptosis independent of cell surface GRP78 function. Par-4 contains …

Pharmacologic Induction Of The Melanocotin 1 Receptor (Mc1r) Pathway Provides Protection Against Sunburn And Enhances Expression Of Antioxidant Enzymes In The Skin, Alexandra Amaro-Ortiz

Theses and Dissertations--Toxicology and Cancer Biology

The inability to tan properly after sun exposure strongly correlates with increased incidence of skin cancer. The melanocortin 1 receptor (MC1R) is a transmembrane Gs-coupled cell surface receptor found on epidermal melanocytes that transmits pro-survival and pro-differentiation signals mediated by the second messenger cAMP. Humans carrying loss-of-function polymorphisms in MC1R signaling exhibit higher incidences of skin cancers including melanoma.

This study focused on the physiologic effects of topical application of forskolin, an adenylate cyclase activator, in extension (Mc1r^e/e) K14-SCF animals, which model the fair-skinned UV-sensitive human. Twice daily application of the drug promoted accelerated pigmentation, increased skin darkening …