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A Signal To Divide: Apoptotic Extracellular Vesicles As Carriers Of Mitogenic And Immunogenic Signals, Safia Essien, Safia Essien

Dissertations & Theses (Open Access)

Efficient replacement of dead cells in epithelial tissue is crucial for maintaining barrier function and tissue homeostasis. Apoptotic cells can signal to neighboring cells to stimulate proliferation and compensate for cell loss and maintain overall cell numbers in normal physiology and cancer. While dying cells can transmit instructive cues to neighboring cells, the molecular mechanisms that induce cell division are not well understood. Recent evidence suggests that apoptotic bodies (ABs) or apoptotic extracellular vesicles (AEVs) mediate cell-to-cell communication and carry diverse biologically active cellular cargo which can influence cell proliferation. This dissertation visualizes and characterizes AEVs in larval zebrafish and …

Genomic Characterization Of Adolescent And Young Adult Cancers: Investigation Of Ewing Sarcoma Susceptibility And Chornobyl Thyroid Tumors, Olivia Lee

Dissertations & Theses (Open Access)

Adolescent and young adult (AYA) cancers, diagnosed between the ages of 15 and 39, can exhibit distinctive genetic and molecular characteristics. Reported epidemiologic findings and treatment outcomes based on pediatric and adult cancer studies are often not suitable for application to the AYA population, underscoring the need for more thorough genomic research. Advances in sequencing technologies have enabled comprehensive analyses of complex genomic characteristics of AYA cancers, crucial for understanding the underlying biology of these malignancies. Here, I have utilized advanced sequencing techniques and integrated analytic approaches to describe important genomic features in two different AYA cancer types: Ewing Sarcoma …

Role Of The Immune System In The Modulation Of The Mmr-Deficient Intestinal Stem Cell Niche, Shepard Conner

Dissertations & Theses (Open Access)

Mismatch Repair (MMR) is a crucial DNA repair system to maintain genomic integrity in cells that is integrated by specific genes including MLH1, MSH2, MSH6, and PMS2. These genes play a critical role in repairing errors that occur in base pairing by stabilizing the genetic material. When the MMR system fails to correct those errors, MMR deficiency occurs where monoallelic mutations in the MMR genes result in a condition known as Lynch Syndrome (LS). LS makes up approximately 3% of all colorectal cancer (CRC) and is regarded as a hereditary form of CRC, which progresses from MMR-deficient …

Oncogenic Kras And Telomere Biology In Crc Progression, Ronald Depinho

Dissertations & Theses (Open Access)

While colorectal cancer (CRC) patients diagnosed with localized stage disease (as defined by SEER) have a 5-year survival rate of 90%, this rate plunges to 14% for patients diagnosed with metastatic CRC. Consequently, there is an immediate imperative to elucidate the mechanisms that drive the transition to advanced CRC.

Human CRCs carrying oncogenic mutations in the KRAS oncogene, henceforth referred to as KRAS*, exhibit a 25% higher propensity for developing liver metastases. Similarly, in our CRC mouse model, engineered with an inducible Kras* transgene and conditional null alleles of Apc and Tp53 (referred to as iKAP), KRAS* has been …

Investigating The Role Of Il-10 Producing Nkt Cells In Prevention Of Graft Versus Host Disease, Drew Boagni

Dissertations & Theses (Open Access)

The standard curative treatment for hematologic malignancies is allogeneic stem cell transplantation (ASCT), in which the patient’s immune system is replaced with that of a healthy donor. This can lead to cure through the graft versus leukemia (GVL) effect but can also cause graft versus host disease (GVHD), which is characterized by systemic inflammation and organ damage mediated by dysregulated donor T cells. Preclinical studies have shown invariant natural killer T cells (iNKT) cells can prevent GVHD while preserving GVL. iNKT cells are unconventional T cells which recognize glycolipid antigens presented in the context of CD1d. Upon activation, they secrete …

Acute Manipulation Of Erna Level For Dissecting Its Roles In Transcriptional Regulation, Lanxin Bei

Dissertations & Theses (Open Access)

Enhancers are the central genetic elements controlling cell-type and state specific transcription programs to dictate cell fates during development. Mechanistic understanding of enhancer action is important for both biology and disease research. In the human genome, more than 60k human enhancers were found to produce non-coding transcripts named enhancer RNAs (eRNAs). These created a new challenge to understand enhancer functions, which now are not only DNA elements that promote transcription but also RNA-producing transcription units themselves. Importantly, deregulation of eRNAs was associated with various diseases such as cancer, immune disorders, and neurodegeneration. However, the direct role of eRNAs in transcriptional …

Protein L Functionalized Microparticles For Early Detection Of Surface Markers In Heterogeneous Colorectal Lesions, Saleh Ramezani

Dissertations & Theses (Open Access)

Colorectal cancer (CRC) is the third leading cause of cancer-related deaths among both men and women worldwide, a statistic that can be improved with early detection. Increased understanding of the tumor landscape has identified surface antigens that can be utilized to distinguish normal and cancerous tissue lining the colonic lumen. Use of antibodies conjugated to nano/micromaterials offers a means to detect these antigens, however, the heterogeneous nature of tumors makes it unlikely that antibodies against a single antigen will have sufficient sensitivity and specificity to detect all tumors. A versatile micromaterial able to be functionalized with more than one targeting …

Role Of Il-17/Il-17ra Signaling In The Pancreatic Tumor Microenvironment, Susana Castro Pando, Susana Castro Pando

Dissertations & Theses (Open Access)

Pancreatic ductal adenocarcinoma (PDAC) is projected to become the second leading cause of cancer-related deaths. PDAC is characterized by the early establishment of a highly immunosuppressive fibro-cellular tumor microenvironment (TME). Our research has revealed the important role of IL-17 in the development and progression of pancreatic cancer, yet the specific cellular compartment responsible for IL-17-mediated tumor promotion remains unknown. We generated a transgenic mouse model with pancreatic KrasG12D activation and selective deletion of IL-17RA in the epithelial vs. immune component using either genetic manipulation or bone marrow transplantation. Deletion of IL17RA from the pancreatic epithelial compartment delayed premalignant lesion development …

Identifying Functional Enhancers For Fibrotic Gene Regulation In Liver Fibrosis, Parnaz Merikhian

Dissertations & Theses (Open Access)

Liver fibrosis is characterized by progressive activation of proliferating and migrating myofibroblasts that lead to accumulation of extracellular matrix (ECM). These myofibroblasts most arise from activated liver-resident hepatic stellate cells (HSCs). There is an increasing number of patients suffering from liver fibrosis in developed countries including the United States, which is anticipated to continue to grow during 2023-2033 period. TGF-β1 is a key cytokine with a significant role in regulating cell differentiation and adhesion in liver fibrosis. TGF-β signaling triggers gene expression changes in HSCs, including that of fibrotic and EMT-related genes, which then functionally promote HSCs activation and fibrogenesis. …

Preclinical Evaluation Of Immunomodulatory Effects Of Aurora Kinase Inhibition In Human Papillomavirus Positive Cancers, Pragya Sinha

Dissertations & Theses (Open Access)

Human papillomavirus (HPV) is the causative agent of cervical cancer and some cancers of the penis, vulva, vagina, anus, and oropharynx. Current therapies for these cancers include a combination of surgery, radiotherapy, and chemotherapy that often results in permanent, life altering adverse effects. Immunotherapy is partially effective, but with significant recurrence and lower long-term survival. Importantly, there are no few biomarker-selective targeted therapies for these cancers. To address this unmet need, our collaborators conducted a large-scale drug screen and identified Aurora Kinase (AK) inhibitors as a unique class of reagents to induce selective apoptosis in HPV+, but not HPV- human …

Regulation Of De Novo And Maintenance Dna Methylation By Dnmt3a And Dnmt3b, Yang Zeng

Dissertations & Theses (Open Access)

DNA methylation (5-methylcytosine, 5mC) is essential for the regulation of gene expression and integrity of the mammalian genome. It occurs predominantly in the context of CpG dinucleotides to form a symmetrical pattern on both DNA strands, which allows DNA methylation patterns to be semi-conservatively maintained during DNA replication. There are two classes of DNA methyltransferases (DNMTs): DNMT3A and DNMT3B function primarily as de novo methyltransferases that establish DNA methylation patterns, whereas DNMT1 is the major enzyme responsible for maintaining DNA methylation patterns by converting hemi-methylated CpGs to fully methylated CpGs during DNA replication. Two accessory factors also play critical regulatory …

Targeting Metabolic Alterations Associated With Smooth Muscle Α-Actin Pathogenic Variant Attenuates Moyamoya-Like Cerebrovascular Disease, Anita Kaw

Dissertations & Theses (Open Access)

Heterozygous pathogenic variants in ACTA2, encoding smooth muscle α-actin (α-SMA), predispose to thoracic aortic aneurysms and dissections. De novo missense variants disrupting ACTA2 arginine 179 (p.Arg179) cause a multisystemic disease termed smooth muscle dysfunction syndrome (SMDS), which is characterized by early onset thoracic aortic disease and moyamoya disease-like (MMD) cerebrovascular disease. The MMD-like cerebrovascular disease in SMDS patients is marked by bilateral steno-occlusive lesions in the distal internal carotid arteries (ICAs) and their branches. To study the molecular mechanisms that underlie the ACTA2 p.Arg179 variants, a smooth muscle-specific Cre-lox knock-in mouse model of the heterozygous Acta2 R179C variant, termed …

Unique Transcriptional Profiles Underlie Osteosarcomagenesis Driven By Different P53 Mutants, Dhruv Chachad

Dissertations & Theses (Open Access)

Missense mutations in the DNA binding domain of the Trp53 gene are characterized as structural (p53R172H) or contact (p53R245W) mutations based on their effect on the conformation of the protein. These mutations show gain-of-function activities such as increased metastatic incidence as compared to p53 loss, often mediated by their interaction with a repertoire of transcription factors. These interactions are largely context specific. In order to understand the mechanisms by which these mutations drive osteosarcoma progression, we created a mouse model, wherein either the p53 structural mutant p53R172H, or the contact mutant, p53R245W, are expressed specifically in …

Regulation And Function Of Zeb1 Acetylation In Lung Adenocarcinoma Progression And Metastasis, Mabel Perez-Oquendo

Dissertations & Theses (Open Access)

Lung cancer metastasis is leading the causes of cancer-related mortality in the United States and worldwide. Epithelial-to-mesenchymal transition (EMT) is a model for metastasis that results in loss of specialized epithelial cell contacts and acquisition of mesenchymal invasive capacity. Zinc finger E-box-binding homeobox 1 (ZEB1) recognizes and binds to E-boxes of epithelial gene promoters to repress its transcription. ZEB1 has inconsistent molecular weights, which have been attributed to post-translational modifications (PTMs). In the presented dissertation, I specifically addressed the gap in the molecular mechanisms by which PTMs of ZEB1 regulate its ability to induce EMT and how its activity might …

Hypoxia Activated Prodrug And Anti-Angiogenic Therapy Cooperate To Treat Pancreatic Cancer But Elicit Immune Suppressive G-Mdsc Infiltration, Arthur Liu

Dissertations & Theses (Open Access)

We previously showed that the hypoxia-activated prodrug TH-302 (Evofosfamide) reduces intratumoral hypoxia through a tissue remodeling process, initiates tumor vasculature reorganization, and sensitizes aggressive, spontaneous murine models of prostate cancer to immune checkpoint blockade (ICB). In a clinical trial testing the combination of TH-302 with cytotoxic T-lymphocyte-associated protein (CTLA-4) blockade (NCT03098160) a subset of metastatic, ICB refractory patients showed prolonged progression free survival. While these studies highlight hypoxia as therapeutically tractable, we lack a complete understanding of the contribution of the tumor vasculature to hypoxia reduction therapy, as well as the downstream consequences of hypoxia reduction on the cellular composition …

P53 Dimers Elicit Unique Tumor Suppressive Activities Through An Altered Metabolic Program, Jovanka Gencel-Augusto

Dissertations & Theses (Open Access)

p53 is the most frequently mutated tumor suppressor in human cancer. As a tetrameric transcription factor, mutation of the p53 Tetramerization Domain (TD) is a mechanism by which cancers abrogate wild-type (WT) p53 function. p53 TD mutations result in a protein that preferentially forms monomers or dimers. These are also normal p53 states under basal cellular conditions. Although it is accepted that tetrameric p53 is required for full tumor suppressive activities, the physiological relevance of monomeric and dimeric states of p53 is not well understood. We have established in vivo models for monomeric and dimeric p53 which model Li-Fraumeni Syndrome …

Y Chromosome Gene Kdm5d Epigenetically Drives Sex Differences In Colorectal Cancer, Jiexi Li

Dissertations & Theses (Open Access)

Sex exerts a profound impact on cancer incidence, spectrum and outcomes, yet the molecular genetic bases of such sex differences are ill-defined and presumptively ascribed to X-chromosome genes and sex hormones. Such sex differences are particularly prominent in colorectal cancer (CRC) where men experience higher metastases and mortality. A murine CRC model, engineered with an inducible transgene encoding oncogenic mutant KRAS^G12D and conditional null alleles of Apc and Trp53 tumor suppressors (designated iKAP), revealed higher metastases and worse outcomes specifically in males with oncogenic mutant KRAS (KRAS*) CRC. Integrated cross-species molecular and transcriptomic analyses identified Y-chromosome gene histone demethylase …

Adipocytes And Innate Immunity In Systemic Sclerosis, Nancy Wareing

Dissertations & Theses (Open Access)

Systemic sclerosis (SSc; scleroderma) is a chronic systemic autoimmune and connective tissue disorder characterized by vasculopathy, autoimmune phenomena, and widespread fibrosis. Skin thickening and tightening is the cardinal feature of SSc and is responsible, in part, for the considerable morbidity of this disease. There are currently no targeted treatments for skin manifestations in SSc, primarily due to our fragmented understanding of its pathophysiologic mechanisms. In PART I, we report a previously unappreciated link between aberrant expression of the developmental gene sine oculis homeobox homolog 1 (SIX1) in skin-associated adipocytes in SSc skin and the early loss of dermal white adipose …

Uncovering Molecular Targets To Overcome Immunosuppression In Non-Small Cell Lung Cancer With Acquired Tki Resistance, Sonia A. Patel

Dissertations & Theses (Open Access)

Non-small cell lung cancer (NSCLC) remains the leading cause of cancer-related deaths worldwide. Targeted therapeutic agents, such as epidermal-like growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) or monoclonal antibodies targeting vascular endothelial growth factor (VEGF/R), can effectively inhibit upregulated signaling pathways driving tumorigenesis in NSCLC and many other cancers. Unfortunately, however, resistance to such targeted therapies inevitably arise in most patients and can occur through a variety of resistance mechanisms including genomic alterations and upregulation of bypass pathways. Additionally, patients who have acquired resistance to these targeted agents typically have tumors characterized by an immunosuppressive tumor microenvironment and thus …

Functional Analysis Of Daxx In Tumorigenesis Of Pancreatic Neuroendocrine Tumors And Embryonic Development, Chang Sun

Dissertations & Theses (Open Access)

Death domain-associated protein 6 (Daxx) is a histone chaperone specific to Histone 3.3 (H3.3). DAXX interacts with ATRX forming a chromatin remodeling complex, which deposits H3.3 into telomeric and pericentric region of the genome. The importance of Daxx was manifested in embryonic development. The loss of Daxx leads to early lethality in mouse embryos around E6.5. Moreover, sequencing studies have revealed the importance of DAXX in human tumors. Mutually exclusive mutations in DAXX and ATRX occur in about 30% of pancreatic neuroendocrine tumors (PanNETs). Although lots of progress has been made in studying functions of DAXX, we still do not …

Genetic Regulation Of Müllerian Duct Regression, Malcolm Moses

Dissertations & Theses (Open Access)

Mammals, including humans, develop progenitor tissues for both male and female reproductive tract organs before they fully differentiate into a male or female tract. The progenitor tissue for the male reproductive tract is known as the Wolffian duct (WD), and the progenitor tissue for the female reproductive tract is the Müllerian duct (MD). The WD further differentiates into the vas deferens, epididymis, and seminal vesicle, while the MD differentiates into the oviduct, uterus and upper vagina. An essential step in sex differentiation for males is the regression of the MD. This regression initiates with anti-Müllerian hormone (Amh) transcription …

Kir-Based Inhibitory Cars Overcome Car-Nk Cell Trogocytosis-Mediated Fratricide And Tumor Escape, Ye Nmn Li

Dissertations & Theses (Open Access)

Trogocytosis is an active process that transfers surface material from targeted to effector cells. Using multiple in vivo tumor models and clinical data, we report that chimeric antigen receptor (CAR) activation in natural killer (NK) cells promoted the transfer of the CAR-cognate-antigen from tumor to NK cells, resulting in (1) lower tumor antigen density, thus impairing the ability of CAR-NK cells to engage with their targets, (2) induced self-recognition and continuous CAR-mediated engagement, resulting in fratricide of trogocytic antigen expressing NK cells (NK^TROG+) and NK cell hyporesponsiveness. This phenomenon could be offset by a dual-CAR system incorporating both …

Potentiation Of The Immune Checkpoint Blockade Response By Metabolic Modulation Is Predictable Using Molecular Imaging, Renee L. Chin

Dissertations & Theses (Open Access)

Unregulated cell division is a hallmark of cancer. The high metabolic needs of the tumor cells result in nutrient depletion and produce a hostile tumor microenvironment (TME) for antitumor immune cells, protecting the tumor from immune cell-mediated control and immunotherapy. Two of these environmental factors, acidosis and hypoxia, are commonly found in solid cancers. In my thesis, I posited that modulation of tumor acidosis and hypoxia can serve as biomarkers by indicating immunogenicity and tumor sensitivity to immune checkpoint blockade (ICB) as monitored using molecular imaging. Esomeprazole was found to promote tumor immunogenicity and induce tumor control when used to …

Low Molecular Weight Cyclin E Deregulates Dna Replication And Damage Repair To Promote Genomic Instability In Breast Cancer, Mi Li

Dissertations & Theses (Open Access)

Low molecular weight cyclin E (LMW-E) are oncogenic forms of cyclin E that are post translationally generated by neutrophil elastase (NE) mediated cleavage of the 50 KDa full-length cyclin E1 (FL-cycE, encoded by CCNE1gene). The resultant N-terminus deleted (40 amino acids) form of LMW-E is detected in breast cancer cells and tumor tissues, but not in normal mammary epithelial cells or adjacent normal tissues. Unlike FL-cycE, LMW-E drives mammary epithelial cell transformation in human cells and spontaneous mammary tumor formation in transgenic mouse models, but the oncogenic mechanisms of LMW-E and its unique function(s) independent of FL-cycE are not …

S-Acylation Is A Key Regulator Of Orai1/Stim1-Mediated Store-Operated Calcium Entry In T Cells, Savannah J. West Diaz

Dissertations & Theses (Open Access)

Orai1 and STIM1 proteins are the essential components of the Ca²⁺ release activated Ca²⁺ (CRAC) channel which is required for store-operated Ca²⁺ entry (SOCE) in T cells and subsequent signaling events leading to T cell activation, proliferation, and differentiation. Plasma membrane (PM)-localized Orai1 is the pore-forming subunit of the CRAC channel, and STIM1 is the Ca²⁺ sensor localized to the endoplasmic reticulum (ER) membrane in quiescent T cells. T cell receptor (TCR) stimulation leads to depletion of ER Ca²⁺ stores resulting in Ca²⁺ no longer being bound to STIM1. This activates STIM1 by triggering …