Cell Biology Commons^™

A Novel Function For 12-Lipoxygenase In C-Met And Integrin Β4 Axis Crosstalk, Elizabeth Tovar

Wayne State University Dissertations

Cancer cell metastasis is the single most threatening occurrence of tumor progression and predicts patient prognosis as well as survival. Invasion can be regulated by the Met receptor tyrosine kinase (c-Met), integrin beta4, and the lipid enzyme, 12-Lipoxygenase (12-LOX). Therefore we sought to determine if beta4, c-MET and 12-LOX comprise a signaling axis. c-Met is implicated in cancer cell dissemination through regulation of invasion in EMT where cell-cell junctions are disturbed to allow motility. Furthermore, beta4 promotes cellular adhesion to the extracellular matrix through hemidesmosomes. However, the homeostatic signaling functions of beta4's cytoplasmic tail can be hijacked by growth factor …

Mitochondrial Dynamics: Exploring A Novel Target Against Myocardial Ischemia-Reperfusion Injury, Yi Dong

Wayne State University Dissertations

Mitochondrial fusion and fission, collectively termed mitochondrial dynamics, are among the core mechanisms responsible for maintaining mitochondrial health and functional integrity. Dynamin-related protein 1 (DRP1) is a key regulator of mitochondrial fission. Recent studies suggest that i) mitochondrial dynamics, particularly, mitochondrial fission, serves as a mediator of cell fate in the setting of ischemia-reperfusion (IR) injury, and, ii) inhibition of DRP1 and mitochondrial fission provides cardioprotection against IR injury. However, the precise role of DRP1 translocation to mitochondria in the pathogenesis of myocardial ischemia-reperfusion injury has not been established.

Using an established model of hypoxia-reoxygenation (HR) in cultured HL-1 cardiomyocytes, …

Characterization Of Adult Zebrafish Retinal Regeneration Following Two Different Damage Models, Jennifer Lee Thomas

Wayne State University Dissertations

Unlike mammals, zebrafish can regenerate all of their retinal neurons through Müller glial cells, which respond to retinal damage by re-entering the cell cycle to create clusters of progenitor cells. The progenitors continue to proliferate as they migrate to the site of damage, where they ultimately differentiate into new retinal neurons. In contrast, Müller glia of the mammalian retina respond to injury with reactive gliosis, which if persistent, can lead to loss of Müller cell function and devastating vision loss. Despite this, multiple lines of evidence suggest that mammalian Müller glial cells possess a latent ability to regenerate retinal neurons. …

Cxcr2 Macromolecular Complex In Pancreatic Cancer: A Potential Therapeutic Target In Tumor Growth, Shuo Wang

Wayne State University Dissertations

The signaling mediated by the chemokine receptor CXC chemokine receptor 2 (CXCR2) plays an important role in promoting the progression of many cancers, including pancreatic cancer, one of the most lethal human malignancies. CXCR2 possesses a consensus PSD-95/DlgA/ZO-1 (PDZ) motif at its carboxyl termini, which might interact with potential PDZ scaffold/adaptor proteins. We have previously reported that CXCR2 PDZ motif-mediated protein interaction is an important regulator for neutrophil functions. Here, using a series of biochemical assays, we demonstrate that CXCR2 is physically coupled to its downstream effector phospholipase C-β3 (PLC-β3) that is mediated by PDZ scaffold protein Na(+)/H(+) exchange regulatory …

Combating Resistance To Epidermal Growth Factor Recpetor Inhibitors In Triple Negative Breast Cancer, Julie Marie Madden

Wayne State University Dissertations

Triple negative breast cancer (TNBC) patients suffer from a highly malignant and aggressive cancer that lacks an effective targeted therapeutic. Although many TNBCs, both in vitro and in vivo, have increased expression of epidermal growth factor receptor (EGFR), EGFR targeted inhibitors, such as gefitinib (GEF), have yet to demonstrate efficacy. Using mass spectrometry to identify pathways that remain activated in the presence of GEF, we found that components of the mTOR signaling pathway remain phosphorylated. While inhibiting mTOR with temsirolimus (TEM) decreased mTOR signaling, EGFR signaling pathways remained activated and the TNBC cell lines continued to proliferate. However, dual treatment …

Regulation Of Inositol Biosynthesis And Cellular Consequences Of Inositol Depletion: Implications For The Mechanism Of Action Of Valproate, Rania M. Deranieh

Wayne State University Dissertations

Inositol is a six-carbon cyclitol that is ubiquitous in biological systems. It is a precursor for the synthesis of numerous biologically important compounds, including inositol phosphates and phosphoinositides that are essential for cell function and viability. Inositol compounds play a role in membrane formation, gene regulation, signaling, regulation of ion channels, and membrane trafficking. Furthermore, inositol regulates hundreds of genes, including those involved in the biosynthesis of inositol and phospholipids. While transcriptional regulation of inositol biosynthesis has been extensively studied and well characterized, regulation of inositol biosynthesis at the enzymatic level has not been addressed. The current study shows that …

Junctional Sarcoplasmic Reticulum Protein Processing And Trafficking In Cardiac Tissue And Primary Cultured Cardiomyocytes, Naama Sleiman

Wayne State University Dissertations

Junctional SR is an important and unique ER subdomain in the adult myocyte that releases Ca2+ through the actions of an exclusive set of resident proteins. Cardiac calsequestrin (CSQ2) undergoes two co-translational modifications: N-linked glycosylation on 316Asn, and phosphorylation by protein kinase CK2 on a cluster of 3 serines in its tail. In the heart, CSQ2 molecules undergo extensive mannose trimming by ER mannosidase(s), a posttranslational process that often regulates protein breakdown. To investigate CSQ2 protein processing in cardiomyopathy models, studies were performed to test whether CSQ2 glycan structures would be altered in heart tissue from mongrel dogs induced into …

Characterization Of High-Voltage-Activated Calcium Channels In Retinal Bipolar Cells, Qi Lu

Wayne State University Dissertations

Retinal bipolar cells, conveying visual information from photoreceptors to ganglion cells, segregate visual information into multiple parallel pathways through their diversified cell types and physiological properties. Voltage-gated Ca²⁺ channels could be particularly important underlying the diversified physiological properties of different BCs. In this dissertation, I investigated the high-voltage-activated (HVA) calcium current in retinal bipolar cells in mice. In the first part of my dissertation, I characterized multiple bipolar cell-expressing GFP and/or Cre transgenic mouse lines. In the second part of my dissertation, by performing whole-cell patch-clamp recordings, I examined the electrophysiological properties of HVA calcium currents among CBCs and …

Desensitization Of Basal Cell Carcinoma To The Anti-Tumoral Effect Of Vitamin D, Rawia Khasawneh

Wayne State University Dissertations

The relationship between Vitamin D and NMSC is not very clear. Most of human studies in literature in regards to vitamin D and NMSC are epidemiological which are inconsistent and inconclusive. Mechanistic studies about BCC are few, and mostly are animal models or cell cultures. The main goal for this study is to interpret the impact of vitamin D status on the onset and progression and possibly treatment of basal cell carcinoma. Three tissue samples were collected from BCC patients (Cancer, Proximal, and Distal), and from cancer-free individuals from southeast Michigan. This study design helps identifying alterations in the genetic …

Acidic Pericellular Ph: Effects On Proteolysis And Gene Expression As Determined In 3d Models Of Breast Carcinoma, Jennifer M. Rothberg

Wayne State University Dissertations

Among the non-cellular microenvironmental factors that contribute to malignancy of solid tumors is an acidic peritumoral pH. The first objective was to determine if an acidic extracellular pH observed in vivo (i.e., pHe 6.8) affects the activity of proteases, such as cathepsin B, that contribute to degradation of collagen IV by tumor cells when grown in biologically relevant three-dimensional cultures. At pHe 6.8 there were increases in pericellular active cysteine cathepsins and in degradation of DQ-collagen IV, which was partially blocked by a cathepsin B inhibitor. Imaging probes for active cysteine cathepsins localized to tumors in vivo. The amount of …

The Transcriptional Regulation Of Flagellin-Induced Innate Protection Of The Cornea: Role Of Irf1 And Atf3, Gi Sang Yoon

Wayne State University Dissertations

Pre-exposure of the cornea to TLR5 ligand flagellin induces profound mucosal innate protection against infections by reprogramming gene expression. This study explored the flagellin-induced modifications of transcription factor expression and function, specifically of IRF1 and ATF3 in corneal epithelial cells to elucidate the transcriptional mechanisms underlying the protective function of flagellin on the cornea.

Initially we used Superarray to screen for transcription factors and identified Interferon Regulatory Factor (IRF) 1 and Activating Transcription Factor (ATF) 3 as the most drastically affected genes by flagellin pretreatment in P. aeruginosa challenged human corneal epithelial cells (CEC). However, flagellin pretreatment had opposite effects …

Biophysical And Biochemical Factors In The Cellular Microenvironment; Effects On Cell Migration And Invasion, Shalini Menon

Wayne State University Dissertations

Cellular migration is a vital process central to many physiological events including development, immune surveillance and wound healing. However, migration and invasion are not unique to normal physiology, they are also key determinants in the progression of disease states such as cancer. Given the significance of migration it is important that we understand how the process is regulated intracellularly and the various stimuli that can promote it. Even though the role of biochemical factors in mediating migration has been studied extensively, the role of biophysical factors in modulating migration and invasion is less appreciation. The biochemical and biophysical components of …

Cellular Plasticity In White Adipose Tissue: In Vivo Identification Of Bipotent Adipocyte Progenitors In Adult White Adipose Tissue, Yun-Hee Lee

Wayne State University Dissertations

Nutritional and pharmacological stimuli can dramatically alter the cellular composition and phenotype of white adipose tissue (WAT). Nonetheless, the identity of progenitors that contribute to this cellular plasticity in vivo remains poorly understood. Utilizing genetic lineage tracing techniques in combination with in situ imunohistochemical analysis, we demonstrate that brown adipocytes (BA) that are induced by beta3-adrenergic receptor activation (ADRB3) in WAT arise from the proliferation and differentiation of cells that express platelet-derived growth factor receptor alpha (PDGFRA), CD34 and Sca1 (PDGFRA+ cells). PDGFRA+ cells have a unique morphology in which extended processes contact multiple cells in the tissue microenvironment. Surprisingly, …

Hyperosmotic Stress Enzyme Signaling Modulates Oct4, Nanog, And Rex1 Expression And Induces Prioritized Differentiation Of Murine Embryonic Stem Cells, Jill A. Slater

Wayne State University Dissertations

HYPEROSMOTIC STRESS ENZYME SIGNALING MODULATES OCT4, NANOG,

AND REX1 EXPRESSION AND INDUCES PRIORITIZED DIFFERENTIATION OF

MURINE EMBRYONIC STEM CELLS

by

JILL SLATER

MAY 2013

Advisor: Daniel Rappolee, Ph.D.

Major: Physiology

Degree: Doctor of Philosophy

Transcription factor expression and therefore lineage identity in the periimplantation

embryo and its stem cells may be influenced by extracellular stresses,

potentially affecting pregnancy outcome. Cellular stress forces cells to suppress some

normal activities (such as protein synthesis and cell proliferation) in order to repair

stress-damaged macromolecules and restore homeostasis. Therefore, any new

activities that embryonic cells initiate while concurrently funding the demands of the

stress …

The Role Of Cad,Flash And Fam129b In Cancer Cell Survial And Apoptosis, Song Chen

Wayne State University Dissertations

Apoptosis is a normal process in the human body. However, apoptosis is desregulated in cancer cells. Most cancer cells gain resistance to apoptosis, leading to uncontrolled proliferation. In this dissertation, we identified three proteins, associated with apoptosis pathway. 1) CAD, a large multifunctional complex that is invariably elevated in tumor cells, 2) FLASH, a large protein with multiple growth related functions and 3) FAM129B. We demonstrate that CAD could interact with FLASH by using yeast two hybrid, co-immunopreciptation and fluorescence microscopy. In addition, functional analysis using siRNA technology further indicated that CAD could co-operate with FLASH and play roles in …

Molecular Mechanisms Of Strain-Stimulated Intestinal Epithelial Cell Differentiation And Migration, Lisi Yuan

Wayne State University Dissertations

The intestinal epithelium is subjected to repetitive deformation during normal gut function by peristalsis and villous motility. In vitro, cyclic strain promotes intestinal epithelial proliferation and induces an absorptive phenotype characterized by increased dipeptidyl dipeptidase (DPPIV) expression. Schlafen 3 is a novel gene recently associated with cellular differentiation. We sought to evaluate whether Schlafen 3 mediates the effects of strain on the differentiation of IEC-6 intestinal epithelial cells in the absence or presence of cyclic strain. Strain increased Schlafen 3 mRNA and protein. In cells transfected with a control non-targeting siRNA, strain increased DPPIV specific activity. However, Schlafen

3 reduction …

Identifying Sm22 As A Key Player In Arterial Diseases, Jianbin Shen

Wayne State University Dissertations

Background : Expression of vascular smooth muscle cell (VSMC) cytoskeleton markers including SM22 is down-regulated in arterial diseases including atherosclerosis where inflammation and osteochondrogenesis are present. However, the role of this downregulation in arterial pathogenesis is unknown. Hypothesis : Downregulation of SM22 may actively contribute to arterial pathogenesis. Methods : Five Sm22 knockout (Sm22^-/-) mice and their wild type littermates were subjected to carotid artery denudation, an artery injury model. Analyses were conducted on carotid arteries 2 weeks after injury. Primary VSMCs were isolated from mouse aortas and investigated individually at passage 2 to 4. Sm22 knockdown was …

Identification Of Cellular Functions Of Cardiolipin As Physiological Modifiers Of Barth Syndrome, Amit Shridhar Joshi

Wayne State University Dissertations

Cardiolipin (CL) is an anionic phospholipid synthesized in the mitochondrial inner membrane. Perturbation of CL metabolism leads to Barth syndrome (BTHS), a life threatening genetic disorder. I utilized genetic, biochemical and cell biological approaches in yeast to elucidate the cellular functions of CL. Understanding the functions of CL is expected to shed light on the pathology and possible treatments for BTHS.

BTHS is caused by mutations in TAZ1, which encodes a CL remodeling enzyme called tafazzin. BTHS patients exhibit a wide range of clinical presentations, indicating that physiological modifiers influence the BTHS phenotype. A targeted synthetic lethality screen was performed …

A Role For Reactive Oxygen Species In Photodynamic Therapy, Michael Price

Wayne State University Dissertations

Photodynamic therapy (PDT) is based on the ability of certain photosensitizing agents to selectively localize in neoplastic cells and their vasculature. Subsequent irradiation at a wavelength corresponding to a photosensitizer absorbance band excites the photosensitizer molecules, leading to energy transfer reactions and fluorescence. It was initially concluded that the phototoxic effect occurred when energy from the excited state of the photosensitizer was transferred to dissolved oxygen to form singlet oxygen. This product has a very brief half-life and will cause cellular damage only in the immediate vicinity of its formation. But an excited-state photosensitizer can also interact with oxygen to …

Hdm2 Small-Molecule Inhibitors For Therapeutic Intervention In B-Cell Lymphoma, Angela Sosin

Wayne State University Dissertations

Lymphomas frequently retain wild-type (wt) p53 function but overexpress HDM2, compromising p53 activity. Therefore, lymphoma is a suitable model for studying therapeutic value of disrupting HDM2-p53 association by small-molecule inhibitors (SMIs). HDM2 SMIs have been developed and are currently under various stages of preclinical and clinical investigation. This study examined various molecular mechanisms associated and biological effects of two different classes of HDM2 SMIs: the spiro-oxindoles (MI-219) and cis-imidazoline (Nutlin-3) in lymphoma cell lines and patient-derived B-lymphoma cells. Surprisingly, results revealed significant quantitative and qualitative differences between these two agents. At the molecular level, effect of Nutlin-3 was generally more …

The Role Of The Sparc Acidic Domain And Egf-Like Module In Glioma Migration, Invasion, And Signaling, Heather M. Mcclung

Wayne State University Dissertations

THE ROLE OF THE SPARC ACIDIC DOMAIN AND EGF-LIKE MODULE IN GLIOMA MIGRATION, INVASION, AND SIGNALING

HEATHER M. MCCLUNG

Advisor: Sandra A. Rempel, Ph.D.

Major: Pharmacology

Degree: Doctor of Philosophy

We have previously shown that Secreted Protein Acidic and Rich in Cysteine (SPARC) is upregulated in all astrocytoma grades and increases tumor cell migration and invasion. It is thought that different domains within the protein may regulate SPARC functions, suggesting domain-specific targeting to inhibit invasion. To enhance our understanding of SPARC-mediated invasion, we first confirm, at the protein level, our previous cDNA array results, that SPARC increases expression of the …

Palmitoylation And The Yeast Casein Kinase Yck2, Irene Papanayotou

Wayne State University Dissertations

Palmitoylation is a post-translational lipid modification that allows proteins to interact with membranes. In the yeast Saccharomyces cerevisiae, the casein kinase Yck2 is palmitoylated twice at its two C-terminal palmitoyl-accepting cysteine residues, by the palmitoyl-transferring enzyme Akr1. Once palmitoylated, Yck2 traffics through the well characterized secretory pathway to the plasma membrane where it participates in many cellular functions, including bud morphogenesis, cytokinesis, nutrient sensing, and receptor internalization. While the hydrophilic Yck2 is presumably synthesized on cytosolic ribosomes, it gains access to the membrane system by interaction with the six transmembrane-spanning Golgi-localized Akr1. Since palmitoylation occurs at membranes and the palmitoyl-transferases …

The Process Of Autophagy In An In Vitro Model Of Myocardial Ischemia-Reperfusion Injury, Kadija Abounit

Wayne State University Dissertations

Autophagy has been implicated in the pathogenesis of myocardial ischemia-reperfusion (I/R) injury; however, it is not clear whether autophagy is beneficial or detrimental to cell survival. We hypothesized that autophagy is beneficial to cardiomyocytes during I/R and that the paucity of ATP may limit its occurrence. To test this hypothesis, we developed a model of ischemia (hypoxia) involving exposure of HL-1 murine atrial cardiomyocytes to two concentrations of oxygen (0.5% and 2.0%) and 2-deoxyglucose.

Hypoxia, irrespective of the oxygen concentration, caused a dramatic drop in cellular ATP and an increase in the phosphorylation of AMPK (an indication of energy starvation),. …

Cardiac Calsequestrin Phosphorylation And Trafficking In The Mammalian Cardiomyocyte, Timothy Mcfarland

Wayne State University Dissertations

Cardiac CSQ (CSQ2) is a multifaceted protein, capable of binding significant quantities of Ca2+ and altering ryanodine receptor activity at the junctional sarcoplasmic reticulum (SR). Little is known about the trafficking of CSQ2 from its unknown site of biosynthesis, which appears to be of importance as its structure changes in a trafficking-dependent manner in various types of heart failure. Through the use of multiple antibodies specific to classic rough ER markers, and with the creation of CSQ-DsRed tetramer fusion protein, we were able to establish a juxtanuclear localization of rough ER in cardiomyocytes. Using fluorescence confocal microscopy, the translocon complex …

Amphiregulin (Areg) And Epidermal Growth Factor (Egf): Disparate In Egfr Signaling And Trafficking, Andrea Jacqueline Baillo

Wayne State University Dissertations

We have previously shown that SUM-149 human breast cancer cells require an AREG/EGFR autocrine loop for cell proliferation. We also demonstrated that AREG can increase EGFR stability and promote EGFR localization to the plasma membrane. In the presented dissertation we successfully knocked-down AREG expression in SUM-149 cells by lenti-viral infection of AREG shRNA. In the absence of AREG expression, SUM-149 cell growth was slowed, but not completely inhibited. Furthermore, cells infected with AREG shRNA constructs showed an increase in EGFR protein expression by western blot. Immunofluorescence and confocal microscopy showed that following AREG knock-down, EGFR continued to localize to the …

Frazzled And Abelson Interact To Regulate The Actin Cytoskeleton In Drosophila, Bridget Elsa Varughese

Wayne State University Dissertations

Guidance receptors such as Frazzled affect cell shape and motility by directly or indirectly modulating the cytoskeleton. Fra is particularly needed for the formation of the posterior commissures in a developing Drosophila embryo. The cytoplasmic tyrosine kinase, Abelson Kinase (Abl) enhances the loss of commissures observed in fra mutant. Abl physically interacts with Frazzled to help guide commissural axons across the midline. Furthermore, the loss of commissural axons is only seen when the actin dynamics are perturbed. Abl is also known to regulate actin-dependent processes underlying formation of filopodia, microspikes and membrane ruffles. So, we established a Drosophila S2 cell …

Human Trophoblast Survival And Invasion In The Developing Placenta: Autocrine Regulation By Hbegf, Philip Jessmon

Wayne State University Dissertations

HBEGF is a multifunctional protein in early pregnancy that induces cytotrophoblast (CTB) cell differentiation to an invasive phenotype, protects against apoptosis, and is involved in an autocrine signaling mechanism that leads to its own protein synthesis. CTBs exist in a low O₂ environment during the first 10 weeks of implantation, during which they invade the decidualized uterine stroma. Inhibitors of intracellular signaling pathways demonstrated that at 20% O₂ HBEGF induces an increase in cell migration through the ERK, MAPK14, JNK, or PIK3 pathways downstream of signaling through its ERBB receptors. Also downstream of these four pathways, HBEGF induces …

Functional In Vitro Analyses Of Lipid Raft-Associated Cathepsin B: Implication For The Invasive Phenotype Of Inflammatory Breast Cancer, Bernadette Caroline Victor

Wayne State University Dissertations

FUNCTIONAL IN VITRO ANALYSES OF LIPID RAFT-ASSOCIATED CATHEPSIN B: IMPLICATION FOR THE INVASIVE PHENOTYPE

OF INFLAMMATORY BREAST CANCER

by

BERNADETTE C. VICTOR

December 2011

Advisor: Dr. Bonnie F. Sloane

Major: Cancer Biology

Degree: Doctor of Philosophy

Inflammatory breast cancer (IBC) is an aggressive, metastatic and

highly angiogenic form of locally advanced breast cancer. Breast

cancer invasion has been linked to proteolytic activity at the tumor

cell surface. We observed that uPA, uPAR and enzymatically active

cathepsin B were all present in caveolae fractions isolated from

SUM149 cells. Using a live-cell proteolysis assay, we demonstrated

that both IBC cell lines degrade …

Mechanical Forces And Tumor Cells: Insight Into The Biophysical Aspects Of Cancer Progression, Indrajyoti Indra

Wayne State University Dissertations

Mechanical forces play an important role in the regulation of cellular behavior and physiological processes including adhesion, migration, proliferation, tissue repair, embryogenesis and development. In addition, a number of diseases including cancer, have been linked to changes in cellular and extracellular mechanical properties. However, whether a correlation exists between the progression of cancer towards metastasis and mechanical factors has not been clearly defined. Additionally, how a cell responds to changes in extracellular mechanical cues as it gains metastatic abilities is poorly understood. To address these questions, we have utilized a panel of murine breast cancer cell lines with progressive metastatic. …

Induction And Regulation Of Autophagy By Novel Prenylation Inhibitors In Sts-26t Malignant Peripheral Nerve Sheath Tumor (Mpnst) Cells, Komal Madhukar Sane

Wayne State University Dissertations

Prenylation pathways have been targeted via several different compounds that inhibit farnesyl transferase (FTase) and/or geranylgeranyl transferase (GGTase) enzymes in many cellular and animal models of cancer. Some of these have also been evaluated in clinical trials with limited success. Multiple mechanisms of action have been elucidated for such compounds, including cell cycle arrest, proteasome inhibition, apoptosis and most recently, autophagy. However, there is still an urgent need of effective agents of this class of anti-tumor therapeutics. In this dissertation, I sought to delve into this issue by characterizing our novel prenylation inhibitors and their potential as anti-tumor agents. Novel …