Cell Biology Commons^™

Development Of Self-Assembled Polymeric Polyplexes For Microrna Delivery: Toward Treatment Of Alcohol-Associated Liver Disease, Marjina Akter Kalpana

Theses & Dissertations

Self-assembled polymeric polyplexes have the potential to serve as an RNA interference (RNAi) delivery platform for the combined inhibition of CXCR4 and miR-155 in the treatment of alcohol-associated liver disease (AALD). A central challenge in RNA delivery is balancing the extracellular stability of polyplexes, cellular uptake, and intracellular release of RNA cargo. We developed polymeric polyplexes using the CXCR4-antagonist polymer PAMD, designed to target CXCR4 on activated hepatic stellate cells (HSCs) and deliver therapeutic miRNA to activated Kupffer cells (KCs) in fibrotic liver. We improved the polyplexes by cholesterol modification of PAMD and by PEGylation of PAMD-Ch. The cholesterol modification …

Kinase Suppressor Of Ras 2 Regulates Energy Balance And Tumor Initiation, Dianna H. Huisman

Theses & Dissertations

Kinase Suppressor of Ras 2 (KSR2) is a scaffold that facilitates Raf-MEK-ERK signaling and is expressed in the brain, pituitary, and adrenal gland. Here, we demonstrate that KSR2 functions in the adult brain to maintain organismal energy balance and in small-cell lung carcinoma (SCLC) to promote self-renewal and clonogenicity. Disruption of KSR2 in adult mice results in hyperphagia, obesity, reduced metabolic rate, and altered activity. Using spatial transcriptomics, we identify regions of the brain associated with regulation of feeding and energy expenditure with altered gene expression following KSR2 disruption. These findings reveal regions of interest in which targeted KSR2 disruption …

Drivers And Mechanisms Of Golgi Fragmentation As A Modulator Of Disease, Amanda Macke

Theses & Dissertations

The Golgi apparatus plays a pivotal role in post-translational modification, trafficking, and secretion of proteins, ensuring proper cellular function. As a result, its fragmentation has been implicated in multiple pathological conditions, including alcohol-induced liver injury and prostate cancer (PCa). Despite its known impact on cellular homeostasis, the molecular mechanisms governing Golgi fragmentation remain to be clarified. Additionally, we have only just begun to understand the vast consequences of Golgi disorganization on disease progression.

This dissertation investigates the drivers and mechanisms of Golgi fragmentation, with a focus on its role as a modulator of disease. Using both in vitro and in …

Coxiella Burnetii Manipulation Of Membrane Contact Sites In The Intracellular Niche, Margaret F. Sladek

Theses & Dissertations

Coxiella burnetii is a highly infectious and environmentally persistent bacterium that causes the disease Q Fever. Its intracellular home, the Coxiella-Containing Vacuole (CVV), is formed from fusion of host-derived vesicles and is rich in sterols - yet cholesterol accumulation in the CCV is bacteriolytic. Our lab’s goal is to understand how Coxiella manages intracellular cholesterol levels and survives within the host. One way Coxiella may modulate CCV cholesterol is through membrane contact sites (MCS), areas where molecular complexes bridge two organelles and exchange lipids. This thesis explores how Coxiella uses both a mammalian lipid transfer protein and bacterially-encoded effector …

P85Α Degradation Mediated By Ubiquitin E3 Ligase Fbxo21 Offers Therapeutic Potential In Leukemia, Kasidy K. Weber

Theses & Dissertations

Acute myeloid leukemia (AML) is a complex and heterogeneous disease characterized by the clonal expansion of myeloid blasts in the bone marrow. Despite significant therapeutic advances over the years, the prognosis for AML patients remains dismal, with high relapse rates and poor overall survival. The ubiquitin-proteasome system (UPS) plays a critical role in maintaining cellular homeostasis by regulating the degradation of proteins involved in essential processes such as cell cycle control, DNA repair, apoptosis, and various signaling pathways. Given this vital function, targeting ubiquitin E3 ligases within the UPS presents a promising strategy for developing more effective and targeted therapies …

Cis-Regulatory Mechanisms Through Stages Of Erythroid Regenration, Yichao Zhou

Theses & Dissertations

Produced by steady state erythropoiesis, erythrocytes serve as vital regulators of metabolism and life by delivering oxygen to all the cells and tissues. Under acute anemia, steady state erythropoiesis is not sufficient to produce enough erythrocytes, leading to distinct mechanisms needed to regenerate large numbers of mature erythrocytes rapidly. Erythroid regeneration occurs in four stages: activation, expansion and differentiation, resolution, and post-resolution, according to the dynamics of erythrocyte numbers and progenitor activity. Erythroid regeneration throughout this timeline requires some critical extracellular cues, but the intrinsic molecular mechanisms needed to accelerate and decelerate the activity of erythroid progenitors in anemia and …

Identifying The Molecular Determinants Of Lung Metastatic Adaptation In Prostate Cancer, Grace M. Waldron

Theses & Dissertations

Prostate cancer (PC) stands as the primary diagnosed cancer in men in the US at approximately 299,010 cases in 2024 and ranks second globally, posing a significant public health challenge. Clinical presentations vary widely, from indolent to aggressive forms, necessitating stage-specific treatment regimens. Understanding its metastatic nature is critical due to the impact of cancer cell dissemination on disease morbidity, with bone and visceral organs serving as key sites of metastasis. Despite bone metastasis being the most common site for metastasis, visceral metastases at sites such as the liver and lungs correlate with poorer survival, emphasizing the role of microenvironmental …

Identification Of Mitotic Phosphatases And Cyclin K As Novel Molecular Targets In Pancreatic Cancer, Yi Xiao

Theses & Dissertations

Pancreatic cancer is a highly lethal disease worldwide. Given the limited effectiveness of current regimens in restricting tumor progression, it is imperative that potential molecular targets be identified to offer valuable insights into alternative therapeutics. By using a phosphate-binding tag (Phos-tag) technique, previous studies have identified several Hippo pathway-related proteins and kinases required for cancer growth or paclitaxel resistance. This work has screened various phosphatases and cyclins/cyclin-dependent kinases (CDKs) as potential cancer targets, but specifically focuses on characterizing the roles of carboxy-terminal domain small phosphatase like 2 (CTDSPL2), apoptosis-stimulating protein of p53-2 (ASPP2), and Cyclin K in pancreatic cancer.

CTDSPL2 …

Mucins: Drivers Of Cancer Cell And Microenvironment Crosstalk In Pancreatic Cancer, Xiaoqi Li

Theses & Dissertations

Mucins facilitate the pancreatic cancer (PC) initiation, progression, and metastasis. Among mucins, MUC4 has been reported to inhibit lymphokine-activated cell killing and induce the apoptosis of cytotoxic T-cells. Counterintuitively, MUC4 expression is upregulated by multiple T-cell-secreted cytokines, such as IFN-γ, IL-17, and stroma-secreted factors like retinoic acid. Previously, we have identified that nuclear receptor coactivator 3 (NCOA3) regulates the MUC1 and MUC4 expression by increasing chromatin accessibility and maintaining protein stability. However, the comprehensive crosstalk mediated by MUC4 in cancer cells and T-cells and how its upstream regulator, NCOA3, modifies the cancer cell-intrinsic behavior is still elusive. Here, we show …

Characterization Of Trafficking And Metabolic Functions Of The Endocytic Regulator Ehd1 In Ewing Sarcoma, Sukanya Chakraborty

Theses & Dissertations

Ewing sarcoma (EWS) is the second most common bone malignancy in children and adolescents. Despite improvement in survival due to advances in multimodality treatment strategies, patients with metastatic or recurrent disease have very poor outcomes. Overexpression of the EPS15 Homology Domain containing 1 (EHD1) protein has been linked to tumorigenesis but whether its core function as a regulator of intracellular traffic of cell surface receptors plays a role in oncogenesis remains unknown.

Studies presented in this dissertation establish that EHD1 overexpression is a feature of nearly 90% EWS patient tumors with high EHD1 expression specifying shorter patient survival. ShRNA-knockdown and …

Role Of The Ganglioside Gd2 And Its Biosynthetic Enzyme Gd3 Synthase In Prostate Cancer Tumorigenesis, Aaqib Bhat

Theses & Dissertations

Despite significant advancements in managing localized prostate cancer (PC), which have notably increased survival rates, advanced PC continues to be a leading cause of cancer- related fatalities. The discovery of new pathways that can be targeted to inhibit tumor growth in PC could pave the way for innovative treatment strategies. The disialylganglioside GD2 is an FDA-approved target for antibody therapies in neuroblastoma and has not been extensively studied in the context of PC. The work done in this thesis reveals that GD2 is present on a minor subset of PC cells in certain patients and is more prevalent in metastatic …

Synergetic Signaling Between The Chlamydia Secreted Effectors Tarp And Tmea Regulates Actin Kinetics And Efficient Entry, Matthew Romero

Theses & Dissertations

Chlamydia trachomatis is both the leading cause of non-congenital preventable blindness in developing nations and the leading source of bacterial sexually transmitted infections. As an obligate intracellular pathogen, Chlamydia has an absolute requirement on gaining entry into its host, which is accomplished by manipulating the host actin cytoskeleton to assemble engulfment structures that drive pathogen entry. In support of this, Chlamydia secretes the effectors TarP and TmeA via a type-III secretion system, whose respective signaling outputs operate synergistically to generate rapid actin kinetics and efficient pathogen engulfment. Rapid actin recruitment characteristic of invading Chlamydia is derived from a collaborative interaction …

Samd14 Mechanisms In Stress Erythropoiesis, Suhita Ray

Theses & Dissertations

Red blood cells (RBCs) essential for tissue oxygenation are generated by the process of erythropoiesis. Any decrease in the RBCs or the oxygen-carrying molecule hemoglobin leads to anemia, affecting nearly 1.62 billion people worldwide. Stress erythropoiesis describes the process of accelerating RBC production during anemia, to compensate for the loss. Among several important mediators of stress erythropoiesis, paracrine signals - involving cooperation between Stem Cell Factor (SCF)/Kit signaling and other signaling inputs – are required for the activation/function of a unique population of progenitor cells - stress erythroid progenitors (SEPs). Biological mechanisms controlling SEP activation and function can be distinct …

The Co-Oncogenic Function Of Ecdysoneless Protein With Erbb2 In Mammary Epithelial Cells, Benjamin B. Kennedy

Theses & Dissertations

The Ecdysoneless (ECD) protein is highly evolutionarily conserved and ubiquitously expressed across human tissues. ECD has established roles in cell cycle regulation, embryogenesis, cell survival, and RNA biogenesis. ECD mRNA and protein are overexpressed in breast cancer, and its overexpression correlates with poor patient survival, especially in ErbB2/HER2-positive breast cancer. This thesis work investigates the co-oncogenic role of ECD in ErbB2-driven oncogenesis using immortalized mammary epithelial cells. Here, we show that ECD and ErbB2 overexpression in immortalized human mammary epithelial cells increases cancer traits, such as invasion, migration, and anchorage independent growth. Significantly, ECD+ErbB2 co-overexpression further enhanced all oncogenic traits. …

Development Of Combination Therapy Strategies To Treat Cancer Using Dihydroorotate Dehydrogenase Inhibitors, Nicholas Mullen

Theses & Dissertations

Cancer cells require supraphysiologic levels of nucleotide triphosphates to fuel their malignant behaviors, including uncontrolled proliferation, immune evasion, metastasis, and therapy resistance. This requirement is met by hyperactive flux through the de novo pyrimidine and de novo purine pathways. Dihydroorotate dehydrogenase (DHODH) is an essential enzyme in the de novo pyrimidine pathway that can be targeted by FDA approved and experimental drug compounds. A robust body of preclinical evidence, encompassing hundreds of independent studies over several decades, demonstrates impressive activity of DHODH inhibitors in animal models of cancer. Paradoxically, however, all clinical trials to date have failed to demonstrate efficacy …

Characterization Of Ape1 And Dna G-Quadruplex Interaction In Transcription Regulation And Dna Damage Repair, Suravi Pramanik

Theses & Dissertations

Human AP Endonuclease 1 (APE1) is the primary enzyme in the base excision repair (BER) pathway that repairs apurinic/apyrimidinic (AP) sites, the most frequently formed DNA lesions in the genome. Recently, through genome-wide mapping analysis, we have shown that APE1, as well as its post-translationally modified form, acetylated APE1 (AcAPE1), is enriched in the gene regulatory regions. The APE1/AcAPE1-enriched regions also harbor Guanine (G)-rich sequences that fold into DNA secondary structures called G-quadruplexes (G4s). Our lab has demonstrated a strong genome-wide correlation between the occurrence of G4 structures and the binding of APE1 and AcAPE1. However, it is unknown whether …

The Role Of Ubiquitin E3 Ligase Fbxo21 In Steady-State, Stressed, And Malignant Hematopoiesis, Karli J. Wittorf

Theses & Dissertations

Hematopoietic stem cells (HSCs) allow for the formation of all cell types in the blood and maintain these populations throughout a person’s life. The process of hematopoiesis is regulated through a variety of molecular mechanisms that are either signaled from the cell’s environment (extrinsic) or from within the cell itself (intrinsic). One intrinsic mechanism that regulates hematopoietic cell fate decisions is the ubiquitin proteasome system (UPS). The UPS controls protein levels by tagging them with polyubiquitin chains and promoting their degradation through the proteasome. The key component of the UPS is the ubiquitin E3 ligase as this protein is the …

Novel Mechanisms Of Protein Kinase C Α Regulation And Function, Xinyue Li

Theses & Dissertations

Protein kinase Cα (PKCα) is a member of the PKC family of serine/threonine kinases, which have been implicated in regulation of many cellular processes, including cell proliferation, differentiation, survival, and transformation. A large body of evidence from the Black laboratory and others support an anti-proliferative function of PKCα in normal epithelial tissues, including the intestinal mucosa and endometrial epithelium. PKCα is also tumor suppressive in epithelial cancers, such as colorectal cancer (CRC) and endometrial cancer (EC). However, a major obstacle to harnessing the tumor suppressive functions of PKCα to benefit patients is the widespread loss of PKCα expression in tumors. …

Underlying Mechanism Of Ovarian Reserve Preservation From Gonadotoxicity, Yi Luan

Theses & Dissertations

Cancer therapies often lead to premature ovarian insufficiency by ovarian damage and follicle depletion. However, the oocyte death pathway induced by chemotherapies has been debated. Here we clarified the precise mechanism of ovarian depletion induced by cyclophosphamide and doxorubicin. Cyclophosphamide induced direct apoptosis in oocytes rather than overactivation of primordial follicles. Dormant oocytes instead of activated oocytes with high PI3K activity were more sensitive to cyclophosphamide. Although the ABL inhibitor, GNF2, has been proposed to ameliorate the apoptosis of primordial follicles against cyclophosphamide, GNF2 did not prevent the loss of primordial follicles induced by cyclophosphamide in the systems tested. Oocyte-specific …

Post-Transcriptional Control Of The Epithelial-To-Mesenchymal Transition (Emt) In Ras-Driven Colorectal Cancers, Chaitra Rao

Theses & Dissertations

Colorectal cancer (CRC) originates from epithelial cells lining the colon or rectum of the gastrointestinal tract. Most cancer deaths result from a tumor spreading to distant organs; however epithelial cells do not normally migrate from their tissue of origin. To do so, epithelial cells undergo biochemical changes allowing them to acquire behavior similar to motile mesenchymal cells termed the epithelial-to-mesenchymal transition (EMT), which contributes to tumor invasion and metastasis. Our study demonstrated that CRC cells require a molecular scaffold, Kinase Suppressor of Ras 1 (KSR1), and ERK to promote the EMT-like phenotype through the preferential translation of Epithelial Stromal Interaction …

Mechanisms Of Sorting And Fission At The Endosomes, Kanika Dhawan

Theses & Dissertations

Endocytic trafficking is a fundamental cellular process that regulates the transport of lipids and proteins. Our lab focuses on the intracellular trafficking of receptors involved in cellular processes such as cell division, migration, and proliferation. Accordingly, the regulation of these trafficking pathways is tightly controlled, involving a complex series of events, of which a key step is the endosomal fission. Perturbations in the endosomal network can eventually lead to impaired receptor recycling to the plasma membrane (PM) and, therefore, have pathological consequences like Alzheimer’s disease and multiple cancers. Upon internalization, cargo-laden vesicles released from the PM fuse with the sorting …

Characterization Of 1,1-Diarylethylene Foxm1 Inhibitors Against High-Grade Serous Ovarian Carcinoma Cells, Cassie Liu

Theses & Dissertations

Forkhead box M1 (FOXM1) is a member of the conserved forkhead box (FOX) transcription factor family. Over the last two decades, FOXM1 has emerged as a multifunctional oncoprotein and a robust biomarker of poor prognosis in many human malignancies. FOXM1 and its associated oncogenic transcriptional signature are enriched in >85% of ovarian cancer cases, and FOXM1 expression and activity can be enhanced by a plethora of genomic, transcriptional, post-transcriptional, and post-translational mechanisms. As a master transcriptional regulator, FOXM1 promotes critical oncogenic phenotypes in ovarian cancer, including: (1) cell proliferation, (2) invasion and metastasis, (3) chemotherapy resistance, (4) cancer stem cell …

Sox2 Dosage Governs Tumor Cell Identity And Proliferation, Ethan P. Metz

Theses & Dissertations

The stem cell transcription factor SOX2 has been widely recognized for its critical roles during mammalian development. SOX2 expression has also been implicated in more than 20 types of human cancers. Importantly, the expression of SOX2 is regulated at multiple levels, which enables the tight regulation of SOX2 levels. Previous work from our laboratory has shown that elevating SOX2 from an inducible promoter inhibits the proliferation of several human tumor cell types. Other studies have reported that high levels of SOX2 are necessary to maintain lineage plasticity in advanced tumors. Thus, the dosage of SOX2 plays a critical role in …

Novel Molecular Mechanisms Of C-Terminal Eps15 Homology Domain (Ehd) Proteins In Endocytic Trafficking And Primary Ciliogenesis, Tyler M. Jones

Theses & Dissertations

Endocytic membrane trafficking is a key cellular process that is critical for regulating the transport of internalized cargoes such as lipids and receptors. Our lab focuses on understanding the mechanisms and cellular functions of the proteins that regulate this pathway. One family of proteins that has seen significant interest over recent years is the C-terminal Eps15 Homology Domain (EHD) family of proteins. Mammalians have four EHD paralogs (EHD1-4) that are expressed ubiquitously in tissues. These proteins have distinct yet overlapping functions in regulating endocytic pathways. EHD1 has been shown to induce constriction and is recruited to induce fission of tubular …

Determining The Role Of Mir-133a In The Diabetic Heart, Tyler Kambis

Theses & Dissertations

Diabetes mellitus (DM) is characterized by hyperglycemia, hyperlipidemia, and hypoinsulemia, each of which disrupt intracellular mechanisms in the heart. DM is a chronic metabolic disease delineated into two categories: insulin deficient-type 1 DM and insulin resistant-type 2 DM. Although they differ in underlying genetic and physiological factors, both significantly increase the risk of heart failure. Impaired insulin signaling shifts energy dependency from glycolysis towards fatty acid β-oxidation in the DM heart. This DM-induced metabolic shift increases mitochondrial stress leading to mitochondrial dysfunction and cell death in the heart. The metabolically entwined ferroptosis is a novel form of myocardial cell death …

Probing The Role Of Astrocytes In The Pathology Of Fragile X Syndrome With Human Stem Cells, Baiyan Ren

Theses & Dissertations

Fragile X syndrome (FXS) is an X-linked neurodevelopmental disorder related to intellectual disability and the most common monogenic cause of autism spectrum disorder. FXS is mainly caused by an expansion of CGG repeats in the 5’-untranslated region of fragile X mental retardation 1 (FMR1) gene, leading to the loss of expression of fragile X mental retardation protein (FMRP). Astrocytes are the most abundant glial cells in the central nervous system (CNS). Loss of FMRP in astrocytes has been found to contribute to structural and functional synaptic deficits in the Fmr1-KO mouse model. The contribution of human astrocytes, however, to the …

A Pkcα-Mediated Growth Suppressive Mek-Erk Signaling Axis In Intestinal Epithelial Cells, Navneet Kaur

Theses & Dissertations

Members of the protein kinase C (PKC) family of serine/threonine kinases are involved in regulation of fundamental cellular functions, including proliferation, differentiation, survival, migration, and transformation. Increasing evidence points to anti-proliferative and tumor suppressive role of PKCs. Our laboratory and others have reported that the classical PKC isozyme, PKCαnegatively regulates proliferation and tumorigenesis in the intestinal epithelium. Our laboratory has further determined that PKCα signaling induces a program of cell cycle withdrawal in intestinal epithelial cells that involves downregulation of the pro-proliferative proteins, cyclin D1 and Id1, and upregulation of the cyclin dependent kinase (CDK) inhibitor, p21^Cip1. Unexpectedly, …

Usp11 And Usp7 Deubiquitinases Regulate Sprtn Auto-Proteolysis And Sprtn-Mediated Dna-Protein Crosslink Repair, Megan C. Perry

Theses & Dissertations

DNA repair pathways that recognize and remove damaged DNA are vital for maintenance of genomic stability and prevention of tumorigenesis. Conversely, these pathways may be robust in tumor cells, thus diminishing the anti-cancer potential of available therapies. DNA-protein crosslinks (DPCs) are particularly deleterious DNA adducts that occur when proteins become irreversibly covalently bound to the DNA. DPCs represent a diverse group of lesions, as any protein can be crosslinked to the DNA duplex by non-specific crosslinking agents like reactive aldehydes and radiation. Additionally, functional DNA-binding proteins such as topoisomerases may become permanently crosslinked to DNA ends by abortive enzymatic processes …

Molecular Mechanisms Of Aberrant Protein Glycosylation In Pancreatic Cancer Stemness And Metastasis, Frank Leon

Theses & Dissertations

A myriad of genetic and other abnormal changes underlies the aggressiveness and dissemination properties observed in pancreatic cancer (PC). Aberrant protein glycosylation is a commonly observed feature in PC. The modification of protein O-glycosylation is mediated by glycosyltransferases, which attach and sequentially elongate monosaccharides on Serine/Threonine (Ser/Thr) motifs. Aberrant glycosylation is recognized as an emerging hallmark of cancer where a disruption in normal glycosylation results in irregular O-glycans.

This dissertation research has investigated the consequences of aberrant protein glycosylation on stemness and enhancement of metastatic properties in pancreatic ductal adenocarcinoma (PDAC). Several publications have reported aberrant O-glycosylation increases in oncogenic …

Role Of Endocytic Machinery Regulators In Egfr Traffic And Viral Entry, Insha Mushtaq

Theses & Dissertations

STUDY 1: Role of endocytic regulator EHD1 and its binding partner RUSC2 in EGFR traffic

Abstract

Epidermal growth factor receptor (EGFR) is a prototype receptor tyrosine kinase and an oncoprotein in many solid tumors. Cell surface display of EGFR is essential for cellular responses to its ligands. While post activation endocytic trafficking of EGFR has been well elucidated, little is known about mechanisms of basal/pre-activation surface display of EGFR. Here, we identify a novel role of the endocytic regulator EHD1 and a potential EHD1 partner, RUSC2, in cell surface display of EGFR. EHD1 and RUSC2 colocalize with EGFR in vesicular/tubular …