Cell and Developmental Biology Commons^™

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

Dissertations and 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 …

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

Dissertations and 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 …

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

Dissertations and 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 …

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

Dissertations and 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 …

Adipocytes And Innate Immunity In Systemic Sclerosis, Nancy Wareing

Dissertations and 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 …

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

Dissertations and 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 …

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

Dissertations and 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 …

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

Dissertations and 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 …

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

Dissertations and 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 …

Genetic Regulation Of Müllerian Duct Regression, Malcolm Moses

Dissertations and 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 …

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

Dissertations and 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 …

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

Dissertations and 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 …

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

Dissertations and 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 and 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 and 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 …

Med12 Is A Critical Regulator Of Neural Crest Lineage And Nervous System Myelination, Fatma Betul Aksoy Yasar

Dissertations and Theses (Open Access)

The Mediator complex (MED) is a multi-subunit protein complex integral to the eukaryotic transcription machinery. MED12 is a Cdk8- regulatory kinase module subunit directly implicated in human disease and is genetically altered in neurological disease and cancer. Numerous attempts at generating an in vivo system to study the role of Med12 failed due to embryonic lethality associated with germline or developmental disruption of Med12 gene. To understand the cellular and molecular processes associated with its role in disease, we generated multiple mouse models with targeted depletion of MED12 in distinct cellular lineages. Our genetically engineered models with induced and conditional …

The Adar-Mavs Pathway Is A Critical Mediator Of The Innate Immune System In Pancreatic Development And Cancer, Dhwani Rupani

Dissertations and Theses (Open Access)

Adenosine deaminase acting on RNA (ADAR) is an RNA-binding protein that deaminates adenosine (A) to inosine (I). A-to-I editing is an important post-transcriptional mechanism to prevent recognition of endogenous RNA by MDA5, a cytosolic RNA sensor. Activation of MDA5 by viral RNA can stimulate the innate immune system. Thus, ADAR-mediated RNA editing is crucial to distinguish “self” from “non-self”. ADAR has an important role in gene regulation as A-to-I editing alters RNA processing affecting both RNA and protein abundance. Given its importance in regulating innate immunity and transcript abundance, aberrations in Adar expression are implicated in developmental deformities and carcinogenesis. …

Ankyrin Dependent Mitochondrial Function And Bioenergetics In The Heart, Janani Subramaniam, Janani Subramaniam

Dissertations and Theses (Open Access)

ANK2 mutations in patients are associated with numerous arrhythmias, cardiomyopathies, and other heart defects. In the heart, AnkB, the protein encoded by ANK2, clusters relevant ion channels and cell adhesion molecules in several important domains; however, its role at Mitochondria Associated ER/SR Membranes (MAMs) has yet to be investigated. MAMs are crucial to mitochondrial function and metabolism and are signaling hubs implicated in various cardiac pathologies. Among several functions, these sites mediate the direct transfer of calcium from the ER/SR to the mitochondria to modulate ATP synthesis. Given that mitochondrial function and energy production are paramount to cardiovascular heath, …

Integrin-Mediated Mechanotransduction Controls Activation Of Yap And Invasive Growth Of Breast Cancer, Xiaobo Wang

Dissertations and Theses (Open Access)

Tumor extracellular matrix (ECM) stiffness is correlated with the aggressiveness of breast cancer. Integrin-mediated adhesion and signaling are crucial for mammary tumorigenesis and tumor progression, in which focal adhesion kinase (FAK) - Src family kinases (SFKs) serves as a hub to relay the mechanical cues from the ECM. We have investigated the mechanisms through which integrin signaling controls mammary tumorigenesis and found that integrin-mediated mechanotransduction controls invasive growth of breast cancer cells in stiff matrices through activation of FAK and YAP. Mechanistic studies revealed that integrin signaling induces - via activation SFKs - tyrosine phosphorylation and inactivation of LATS1 and …

Regulation Of Systemic And Cellular Metabolism In Prostate Cancer By Camkk2 And Elucidation Of Atgl’S Role In Disease Progression, Dominik Awad

Dissertations and Theses (Open Access)

The androgen receptor (AR) is the major driver of prostate cancer; hence, men with progressing disease are treated with androgen deprivation therapy (ADT). However, the majority of patients will relapse within 2-3 years due to multiple AR reactivation mechanisms. Thus, AR and the processes downstream of the receptor remain central drivers of prostate cancer. A direct target of AR is CAMKK2, a gene coding for the serine/threonine kinase Ca^2+/calmodulin-dependent protein kinase kinase 2 (CAMKK2), a protein upregulated in advanced prostate cancer. CAMKK2 modulates many of its pathological effects through the phosphorylation and activation of the 5' AMP-activated …

Grk3 Connects Angiogenesis And Neuroendocrine Differentiation In Prostate Cancer By Activating Hdac2 That Epigenetically Represses Tsp1 And Rest, Samira Naderinezhad

Dissertations and Theses (Open Access)

Prostate cancer (PCa) is the second most frequent cancer and the second leading cause of mortality in men in the United States. Neuroendocrine prostate cancer (NEPC) is the aggressive subset of castration-resistant prostate cancer (CRPC), found in ~20% lethal CRPC. The mechanisms underlying the progression of PCa to NEPC are still largely unclear, and new drug targets are desperately needed. NEPC is highly vascularized (angiogenic) and characterized by high expression of neuroendocrine markers. However, direct molecular links connecting angiogenesis and neuroendocrine differentiation are elusive.

Since epigenetic regulation has been implicated in NEPC progression, we examined expression patterns of 147 epigenetic …

Genomewide Crispr/Cas9 Screen Identifies Network Of Protein Complexes That Regulate Trim24, Lalit Patel

Dissertations and Theses (Open Access)

TRIM24 is an oncogenic chromatin reader that is frequently overexpressed in human tumors and associated with poor prognosis. However, TRIM24 is rarely mutated, duplicated, or rearranged in cancer. This raises questions about how TRIM24 is regulated and whether changes in its regulation are responsible for its activity in cancer.

To investigate this possibility, I performed a genomewide CRISPR/Cas9 screen library using fluorescence activated cell sorting (FACS) to identify regulators of TRIM24. The screen was enabled by two innovations. I engineered cells with an in-frame knock-in of mClover3 to the endogenous copy of TRIM24 to allow fluorescent monitoring of TRIM24 expression …

Yap And Taz Are Required For Neural Crest-Derived Cardiovascular Development, Shannon Erhardt

Dissertations and Theses (Open Access)

Congenital heart defects (CHDs) are the most common human birth defect, occurring in ~1/100 newborns, and are a leading cause of early infant death. Cardiac neural crest cells (NCCs) are a migratory and multipotent cell population known to aid in the development of the cardiac outflow tract (OFT), valves, and interventricular septum, during embryogenesis. Yap and Taz are downstream effectors of the fundamental Hippo signaling pathway and are vital for proper organ and tissue development, yet their role in neural crest (NC)-derived heart formation is still largely unknown. We generated Yap and Taz conditional knockout (CKO) mice using a Cre-lox …

The Role Of The Hypoxia-Inducible Factor 2 In Pancreatic Cancer: Mechanisms Of Tumor Immunosuppression And Intestinal Radioprotection, Carolina Garcia Garcia

Dissertations and Theses (Open Access)

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with dismal prognosis. The only curative option for patients is surgery, but over 80% of patients are not surgical candidates. Unfortunately, PDAC is resistant to the three remaining options. PDAC is characterized by a profoundly hypoxic and immunosuppressive stroma, which contributes to its therapeutic recalcitrance. Alpha-smooth muscle actin+ (αSMA+) cancer-associated fibroblasts (CAFs) are the most abundant stromal component, as well as mediators of stromal deposition. The hypoxia-inducible factors (HIF1 and HIF2) coordinate responses to hypoxia, yet, despite their known association to poor patient outcomes, their functions within the PDAC tumor microenvironment (TME) …

Roles Of Oxidative Stress And Dna Methylation In Cigarette Smoking-Induced Accelerated Acute Myeloid Leukemia Progression, Mary Figueroa

Dissertations and Theses (Open Access)

Acute myeloid leukemia (AML) is a commonly diagnosed cancer in smokers. When current or former smokers have AML, they have worse survival compared to never smoking patients. This has been observed clinically for decades, but then it is unknown how smoking leads to worsened AML survival. Smoking causes oxidative stress and altered DNA methylation that persists for decades in peripheral blood mononuclear cells, but these changes from smoking have not been evaluated in the context of AML. We hypothesize that smoking-induced molecular changes, including altered DNA methylation associated with poor AML prognosis, promote AML. We developed a novel model to …

Non-Photic Mechanisms Of Entrainment In Bmal1 Deficient Conditions, Jamie Tran

Dissertations and Theses (Open Access)

Maintaining our internal circadian (i.e. 24 -hour) clock is imperative to our daily biological and mental well-being. Large epidemiological studies have shown that disruptions of our circadian rhythms can lead to poor mental health, metabolic diseases, and various types of cancer. Various external cues that have become a part of the modern times such as electricity, shift -work, rapid travel across various time zones, easier access to nutritionally unbalanced food items, and various rigid social demands have deleterious effects on our internal clock, and generally reduce robustness of the circadian clock. The two following projects aim to examine two fundamental …

The Novel Role Of Dnmbp In Kidney Development, Brandy Walker

Dissertations and Theses (Open Access)

Congenital anomalies of the kidney and urinary tract (CAKUT) accounts for nearly one-fourth of all birth defects and more than 40% of pediatric end-stage renal disease, yet only 10-20% of CAKUT cases have a known monogenetic cause. Human kidneys are composed of up to a million epithelial tubules called nephrons. Disruption of nephron development is one of the many congenital anomalies that cause CAKUT, often resulting in chronic or end-stage renal disease which requires transplant. During nephron epithelialization, the formation of stable cadherin-mediated adhesion junctions is essential for maintaining cell-cell contacts. To understand the cell behaviors underlying abnormalities in renal …

Novel Regulators Of Cellular Secretion Alter The Tumor Microenvironment To Drive Metastasis, Rakhee Bajaj

Dissertations and Theses (Open Access)

Lung cancer is a highly aggressive disease responsible for ~25% of all cancer-related deaths, due in part to its proclivity to metastasize. Treating metastasis holds potential for improving patient survival but requires a deeper investigation into the underlying mechanisms. Some of these processes that can regulate metastasis are: (1) Oncogenic targets of epithelial micro-RNAs (miRNAs) are epigenetically de-repressed upon loss of the miRNAs during epithelial-to-mesenchymal transition (EMT) and in cancer. EMT confers plasticity and fitness to cancer cells promoting their survival through the metastatic cascade. This cascade and EMT are initiated by loss of the miRNA200 family (miR-200) and the …

Exploiting Chemogenetic And Genetic Interactions In Human Cells As An Avenue For New Therapeutic Opportunities, Medina Colic

Dissertations and Theses (Open Access)

The advent of CRISPR technology and its adaptation to the mammalian genome made whole-genome knockout screens possible directly in human cells. Gene knockout answers how essential that gene is for cell fitness and proliferation. Genes showing moderate to severe fitness defects are called essential genes and provide insights into disease-specific candidate therapeutic targets. Additionally, CRISPR offers other applications for genome editing. Two applications this dissertation is based on are 1) combination of gene knockout and drug treatment, which enables the identification of chemogenetic interactions, or gene mutations that enhance or suppress the activity of a drug, and 2) combinatorial editing, …

An Investigation Of Epigenetic Mechanisms Driving The Biology Of Head And Neck Squamous Cell Carcinoma, Scot Carson Callahan

Dissertations and Theses (Open Access)

Head and neck squamous cell carcinoma (HNSCC) is the 6th most common cancer worldwide and is associated with significant morbidity and mortality. To date, the majority of work in the field has focused on genomic alterations such as mutations and copy number alterations. However, the clinical success of targeted therapies that exploit known genomic alterations, such as EGFR mutations, has remained mixed. Over the past decade, the importance of epigenetic regulators has come to the forefront, with the realization that many of these genes are mutated in cancer. Despite this realization, the role of epigenetics in regulating tumorigenesis, progression and …