Medical Molecular Biology Commons^™

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 …

Mechanism Of Rare Variant In Acta2, P.Arg149cys, Driving Diverse Vascular Disease, Kaveeta Kaw

Dissertations & Theses (Open Access)

Heterozygous variants in ACTA2 (smooth muscle (SM) α-actin) predispose to thoracic aortic aneurysms and dissections (TAAD) and early-onset coronary artery disease (CAD). The most common ACTA2 mutation is a genetic alteration of arginine 149 to a cysteine, ACTA2 p.Arg149Cys, which accounts for disease in 24% of all ACTA2 mutation carriers.(1) ACTA2 p.Arg149Cys mutation carriers present with either TAAD or CAD but rarely have both diseases. To identify the molecular mechanisms dictating whether an individual with ACTA2 p.Arg149Cys develops TAAD or CAD, CRISPR/Cas9 technology was used to generate the mutant mouse, Acta2^R149C/+, in a C57BL6 background. Acta2^R149C/+ mice …

Mitochondrial Unfolded Protein Response Regulator Atf5 In Mitochondrial Targeted Therapies In Aml, Ran Zhao

Dissertations & Theses (Open Access)

Mitochondrial unfolded protein response (UPR^mt) is an adaptive transcriptional response induced by damaged proteins accumulated in mitochondria. UPR^mt signaling involves induction of mitochondrial specific chaperones and proteases such as HSP60, LonP1 and ClpP, aiding in the restoration of mitochondrial protein pool homeostasis. However, the cell-protective roles of UPR^mt in the context of mitochondrial stress-induced cell death in AML has not been well explored. We demonstrate that AML cells are susceptible to mitochondrial targeted agents such as ONC201, an agonist of the mitochondrial protease ClpP, and gamitrinib, an inhibitor of mitochondrial chaperone TRAP1, however, these agents also …

The Role Of Ifitm3 In The Immune Response Of Brca-Deficient High Grade Serous Ovarian Carcinoma, Han Cun

Dissertations & Theses (Open Access)

Background: Prior studies showed that BRCA-deficient high grade serous ovarian carcinoma (HGSOC) had increased tumor infiltrating lymphocytes (TILs) compared to BRCA-wildtype (WT). To better understand the underlying immune mechanism in these tumors, a preliminary transcriptome analysis was performed on a set of microdissected HGSOC tumor specimens with BRCA1-mutation, BRCA2-mutation, or WT. This demonstrated an upregulation of IFITM3, an essential gene in modulating immune function. Based on these findings, we hypothesized that BRCA-deficient HGSOC have increased DNA damage leading to upregulation of IFITM3 and subsequent increase in antigen presentation and T-cell activation.

Methods: Following IRB approval, preliminary transcriptome analysis was performed …

Vascular Disease Pathogenesis In Smooth Muscle Dysfunction Syndrome And Majewski Osteodysplastic Primordial Dwarfism Type Ii, Jamie Wright

Dissertations & Theses (Open Access)

Vascular diseases are a leading cause of morbidity and mortality world-wide. Understanding their pathogenesis is crucial to better diagnosis and management of these life-threatening conditions. Through the study of rare mutations that lead to early onset and severe vascular diseases, we can elucidate underlying mechanisms for vascular disease pathogenesis and develop better treatments to prevent and manage more common causes of vascular diseases. In this study we look at two rare diseases that lead to severe vascular phenotypes, Smooth Muscle Dysfunction Syndrome (SMDS) and Majewski Osteodysplastic Primordial Dwarfism Type II (MOPDII). SMDS is a rare condition due to pathogenic variants …

Hyperpolarized Carbon-13 Magnetic Resonance Measurements Of Tissue Perfusion And Metabolism, Keith Michel

Dissertations & Theses (Open Access)

Hyperpolarized Magnetic Resonance Imaging (HP MRI) is an emerging modality that enables non-invasive interrogation of cells and tissues with unprecedented biochemical detail. This technology provides rapid imaging measurements of the activity of a small quantity of molecules with a strongly polarized nuclear magnetic moment. This polarization is created in a polarizer separate from the imaging magnet, and decays continuously towards a non-detectable thermal equilibrium once the imaging agent is removed from the polarizer and administered by intravenous injection. Specialized imaging strategies are therefore needed to extract as much information as possible from the HP signal during its limited lifetime.

In …

Identification And Molecular Analysis Of Dna In Exosomes, Jena Tavormina

Dissertations & Theses (Open Access)

Exosomes are heterogeneous nanoparticles 50-150nm in diameter. Exosomes contain many functional cargo components, such as protein, DNA, and RNA. While protein and RNA exosome content has been extensively studied, very little work has been done to characterize exosomal DNA. Here, we demonstrate that exosomal DNA is heterogeneous and its packaging into exosomes is dependent on the cell of origin. Furthermore, through a rigorous assessment of various isolation methods, we identify Size Exclusion Chromatography (SEC) as the best method for the isolation of exosomal DNA for downstream applications. Additionally, we evaluate the methylation status of exosomal DNA and demonstrate that exosomal …

Development Of Rational Combination Therapy With Parp Inhibitors And Kinase Inhibitors In Tnbc, Wen-Hsuan Yu

Dissertations & Theses (Open Access)

Poly (ADP-ribose) polymerase inhibitors (PARPi) emerge as potential targeting drugs for BRCA-deficient cancers including triple negative breast cancer (TNBC). However, it has been reported that a subgroup of patients even with BRCA mutation fails to respond to PARPi in multiple clinical trials. In this study, we identified c-Met, a tyrosine kinase, phosphorylates PARP1 at Y907 and that the phosphorylation increases PARP1 activity, thereby rendering cancer cells resistant to PARPi. The combination of c-Met inhibitors (METi) and PARPi has a synergistic effect for c-Met overexpressed TNBC in vitro and in vivo. In addition to c-Met, through functional analysis, we found …

Regulation Of Breast Cancer Initiation And Progression By 14-3-3zeta, Chia-Chi Chang

Dissertations & Theses (Open Access)

14-3-3ζ is a ubiquitously expressed family member of proteins that have been implicated to have oncogenic potential through its interactions and involvement in cancer initiation and progression. 14-3-3ζ belongs to the highly conserved 14-3-3ζ protein family and modulates numerous pathways in cancer. Overexpression of 14-3-3ζ is an early event, occurs in more than 40% of human breast cancer cases, and is associated with disease recurrence and poor prognosis. Metabolic reprogramming is a hallmark of cancer. Cancer cells elevate aerobic glycolysis to produce metabolic intermediates and reducing equivalents, thereby facilitating cellular adaptation to the adverse environment and sustaining fast proliferation. Interestingly, …

Targeting Oncogenic Mirnas With Small Molecules For Breast Cancer Therapy, Paloma Del C. Monroig

Dissertations & Theses (Open Access)

The crucial role of microRNAs (miRNAs) in cancer pathobiology has driven the introduction of new drug development approaches such as miRNA inhibition. In order to advance miRNA-therapeutics, there is a need to develop screening strategies that can target tumors in a specific way. Small molecule inhibitors represent an attractive approach to pursue this. However, the absence of molecular structures for most of the miRNAs makes it very difficult to predict which inhibitors can bind to them. Herein we designed a strategy to screen for small molecules by assesing whether they could directly bind/ interact with miR-10b/miR-21. As part of our …

Methylation Of Egfr By Arginine Methyltransferase Prmt1 Enhances Egfr Signaling And Cetuximab Resistance, Hsin-Wei Liao

Dissertations & Theses (Open Access)

Protein modifications of epidermal growth factor receptor (EGFR) intracellular domain are well known regulators of EGFR functions whereas those of its extracellular domain remain relatively unexplored. Here, we report that methylation at R198 and R200 of EGFR extracellular domain by protein arginine methyltransferase 1 (PRMT1) upregulates its binding to EGF and subsequent receptor dimerization and signaling activation. Methylation-defective EGFR mutant reduced tumor growth in mouse orthotopic xenograft model. Importantly, increased EGFR methylation sustains its signaling activation and cell proliferation in the presence of therapeutic EGFR monoclonal antibody, cetuximab. EGFR methylation level also correlates with higher recurrence rate after cetuximab treatment …

Multilevel Deregulation Of Survival Mechanisms In Npm-Alk+ T-Cell Lymphoma, Deeksha Vishwamitra

Dissertations & Theses (Open Access)

The anaplastic lymphoma kinase (ALK) is a single chain transmembrane receptor tyrosine kinase that belongs to the insulin receptor superfamily. Other members of this superfamily include the insulin receptor (IR), type I insulin-like growth factor receptor (IGF-IR), and the leukocyte tyrosine kinase. The common structural finding among these tyrosine kinases is the YXXXYY motif present within their respective tyrosine kinase domains. Binding of its ligands causes ALK receptor homodimerization and protein kinase activation. ALK has been previously shown to play a significant role during early developmental stages. In human embryos, the expression of ALK is mainly seen in …

The Kras/Mapk Pathway And Ligand Independent Activation Of Erα: Implications For The Treatment Of Endometrial Cancer, Kari Ring

Dissertations & Theses (Open Access)

Hormonal therapy remains a first line option for the treatment of recurrent endometrial cancer (EC), however, many tumors demonstrate de novo or acquired resistance. Member kinases of the PI3K/AKT and Ras/MAPK pathways activate estrogen receptor α (ERα) independent of estrogen, however, few studies have evaluated the role of the Ras/MAPK pathway in predicting response to hormonal therapy in EC. The aims of this project were to evaluate the role of ligand independent activation of ERα in EC and to explore therapeutic implications for the treatment of recurrent EC.

A xenograft model for recurrent EC was used to evaluate the effect …

Development Of Hif-1Α/Hif-1Β Heterodimerization Inhibitors Using A Novel Bioluminescence Reporter Assay System For In Vitro High Throughput Screening And In Vivo Imaging, Yun-Chen Chiang

Dissertations & Theses (Open Access)

Tumor growth often outpaces its vascularization, leading to development of a hypoxic tumor microenvironment. In response, an intracellular hypoxia survival pathway is initiated by heterodimerization of hypoxia-inducible factor (HIF)-1α and HIF-1β, which subsequently upregulates the expression of several hypoxia-inducible genes, promotes cell survival and stimulates angiogenesis in the oxygen-deprived environment. Hypoxic tumor regions are often associated with resistance to various classes of radio- or chemotherapeutic agents. Therefore, development of HIF-1α/β heterodimerization inhibitors may provide a novel approach to anti-cancer therapy. To this end, a novel approach for imaging HIF-1α/β heterodimerization in vitro and in vivo was developed in this study …

Post-Transcriptional Regulation Of Mammalian Gene Expression In Non-Coding Region Of Target Rna, Jing Lin

Dissertations & Theses (Open Access)

Tumor Suppressor Candidate 2 (TUSC2) is a novel tumor suppressor gene located in the human chromosome 3p21.3 region. TUSC2 mRNA transcripts could be detected on Northern blots in both normal lung and some lung cancer cell lines, but no endogenous TUSC2 protein could be detected in a majority of lung cancer cell lines. Mechanisms regulating TUSC2 protein expression and its inactivation in primary lung cancer cells are largely unknown. We investigated the role of the 5’- and 3’-untranslated regions (UTRs) of the TUSC2 gene in the regulation of TUSC2 protein expression. We found that two small upstream open-reading frames (uORFs) …

Direct Effects Of Metformin On Pi3k And Ras Signaling In Endometrial Cancer, David A. Iglesias M.D.

Dissertations & Theses (Open Access)

Metformin has antiproliferative effects through the activation of AMPK and has gained interest as an antineoplastic agent in several cancer types, although studies in endometrial cancer (EC) are limited. The aims of this project were to evaluate pathways targeted by metformin in EC, investigate mechanisms by which metformin exerts its antiproliferative effects, and explore rational combination therapies with other targeted agents.

Three EC cell lines were used to evaluate metformin’s effect on cell proliferation, PI3K and Ras-MAPK signaling, and apoptosis. A xenograft mouse model was also used to evaluate the effects of metformin treatment on in vivo tumor growth. These …

Taz As A Regulator Of Mesenchymal Transformation And Clinical Aggressiveness In Gliomas, Katrina Salazar

Dissertations & Theses (Open Access)

Glioblastoma multiforme (GBM) is an aggressive, high grade brain tumor. Microarray studies have shown a subset of GBMs with a mesenchymal gene signature. This subset is associated with poor clinical outcome and resistance to treatment. To establish the molecular drivers of this mesenchymal transition, we correlated transcription factor expression to the mesenchymal signature and identified transcriptional co-activator with PDZ-binding motif (TAZ) to be highly associated with the mesenchymal shift. High TAZ expression correlated with worse clinical outcome and higher grade. These data led to the hypothesis that TAZ is critical to the mesenchymal transition and aggressive clinical behavior seen in …

Bim Mediates Imatinib-Induced Apoptosis Of Gastrointestinal Stromal Tumors: Translational Implications, David Reynoso

Dissertations & Theses (Open Access)

Gastrointestinal stromal tumors (GISTs) are oncogene-addicted cancers driven by activating mutations in the genes encoding receptor tyrosine kinases KIT and PDGFR-α. Imatinib mesylate, a specific inhibitor of KIT and PDGFR-α signaling, delays progression of GIST, but is incapable of achieving cure. Thus, most patients who initially respond to imatinib therapy eventually experience tumor progression, and have limited therapeutic options thereafter. To address imatinib-resistance and tumor progression, these studies sought to understand the molecular mechanisms that regulate apoptosis in GIST, and evaluate combination therapies that kill GISTs cells via complementary, but independent, mechanisms. BIM (Bcl-2 interacting mediator …

Tp53 As A Biomarker In Head And Neck Squamous Cell Carcinoma, Thomas J. Ow Md

Dissertations & Theses (Open Access)

Currently, there are no molecular biomarkers that guide treatment decisions for patients with head and neck squamous cell carcinoma (HNSCC). Several retrospective studies have evaluated TP53 in HNSCC, and results have suggested that specific mutations are associated with poor outcome. However, there exists heterogeneity among these studies in the site and stage of disease of the patients reviewed, the treatments rendered, and methods of evaluating TP53 mutation. Thus, it remains unclear as to which patients and in which clinical settings TP53 mutation is most useful in predicting treatment failure.

In the current study, we reviewed the records of a cohort …