Cell Biology Commons^™

Mechanisms Underlying The Sensitivity And Resistance Of Gastric Cancer Cells To Met Inhibitors, Rebecca Schroeder

Dissertations and Theses (Open Access)

MET amplification has been clinically credentialed as a therapeutic target in gastric cancer, but the molecular mechanisms underlying sensitivity and resistance to MET inhibitors are still not well understood. Using whole-genome mRNA expression profiling, we identified autophagy as a top molecular pathway that was activated by the MET inhibitor crizotinib in drug-sensitive human gastric cancer cells, and functional studies confirmed that crizotinib increased autophagy levels in the drug sensitive cells in a concentration-dependent manner. We then used chemical and molecular approaches to inhibit autophagy in order to define its role in cell death. The clinically available inhibitor of autophagy, chloroquine, …

Pharmacologic And Genetic Manipulations Of Angiotensin Signaling In Thoracic Aortic Disease Models, Andrew M. Peters

Dissertations and Theses (Open Access)

Thoracic aortic aneurysms and dissections (TAAD) are a major cause of morbidity and mortality in patients. Many different risk factors have been associated TAAD, but hypertension is the largest risk factor. Subsets of TAAD patients have identifiable syndromic genetic diseases, yet a number of genetic non-syndromic patients have been identified. Infusion of angiotensin II into mouse models causes aortic disease through inflammation and fibrosis. An angiotensin type I receptor (AT1R) blocker (ARB) or an angiotensin converting enzyme (ACE) inhibitor (ACEi) can reverse aortic pathology in some mouse models. I set out to better understand the relationship between angiotensin and TAAD …

Persistence Of Enteric Viruses On Surfaces Under Varying Environmental Conditions, Nicole L. Turnage

Graduate Theses and Dissertations

Human enteric viruses such as human norovirus (hNoV) and Aichivirus A (AiV) are common foodborne viruses with hNoVs being identified as the leading causative agent of foodborne illnesses in the U.S. Moreover, hNoVs have been identified as the leading cause of nonbacterial acute gastroenteritis in the U.S. and worldwide. Fomite surface contamination is a major transmission route for enteric viruses. The application of an optimized virus recovery method from fomites is essential for better understanding of virus persistence under varying environmental conditions (EC). This study aimed to optimize a surface sampling method for virus recovery from nonporous food contact surfaces …

Functional Expression Of Programmed Death-Ligand 1 (B7-H1) By Immune Cells And Tumor Cells, Rachel M. Gibbons Johnson

Biology Publications

The programmed death-1 (PD-1) and its ligand PD-L1 (B7-H1) signaling pathway has been the focus of much enthusiasm in the fields of tumor immunology and oncology with recent FDA approval of the anti-PD-1 antibodies pembrolizumab and nivolumab and the anti-PD-L1 antibodies durvalumab, atezolimuab, and avelumab. These therapies, referred to here as PD-L1/ PD-1 checkpoint blockade therapies, are designed to block the interaction between PD-L1, expressed by tumor cells, and PD-1, expressed by tumor-infiltrating CD8+ T cells, leading to enhanced antitumor CD8+ T cell responses and tumor regression. The influence of PD-L1 expressed by tumor cells on antitumor CD8+ T cell …

The Structural And Functional Properties Of A Double Mutant Of Human Acidic Fibroblast Growth Factor (Hfgf-1), Arwa Mohammed Alghanmi

Graduate Theses and Dissertations

Human acidic Fibroblast Growth Factor 1 (FGF-1), a member of the FGF superfamily, is a potent mitogen and heparin-binding protein involved in a broad spectrum of biological processes, including angiogenesis, cell proliferation, and wound healing. Design of hFGF-1 with an increased thermal stability and an enhanced cell proliferation activity is highly desired for wound healing applications. Herein, we have designed the variant of FGF-1 by substituting two important amino residues in the heparin-binding pocket. The variant was overexpressed in Escherichia coli and was successfully purified to homogeneity using an affinity chromatographic procedure. Far-UV circular dichroism spectroscopic analysis showed that the …

Prolonged Growth Hormone/Insulin/Insulin-Like Growth Factor Nutrient Response Signaling Pathway As A Silent Killer Of Stem Cells And A Culprit In Aging, Mariusz Ratajczak, Andrzej Bartke, Zbigniew Darzynkiewicz

NYMC Faculty Publications

The dream of slowing down the aging process has always inspired mankind. Since stem cells are responsible for tissue and organ rejuvenation, it is logical that we should search for encoded mechanisms affecting life span in these cells. However, in adult life the hierarchy within the stem cell compartment is still not very well defined, and evidence has accumulated that adult tissues contain rare stem cells that possess a broad trans-germ layer differentiation potential. These most-primitive stem cells-those endowed with pluripotent or multipotent differentiation ability and that give rise to other cells more restricted in differentiation, known as tissue-committed stem …

Eye Repair In Xenopus Laevis, Cindy Xuan-Mai Kha

UNLV Theses, Dissertations, Professional Papers, and Capstones

Eye development in vertebrates of complex steps that include specific interactions of the neuroectoderm and overlying head ectoderm. The African clawed frog, Xenopus laevis (X. laevis), has a well-characterize eye developmental pathway and is an established model for eye regeneration research. Additionally, Xenopus frogs have high regenerative abilities to regenerate individual eye tissues such as the retina, lens, and cornea. However, it was previously shown that the removal of the specified eye field during the neurulation stage or an eye during the swimming tadpole stage does not permit an eye to regenerate. Here we will describe a model for investigating …

Reversion Of Epithelial-Mesenchymal Transition By A Novel Agent Dz-50 Via Igf Binding Protein-3 In Prostate Cancer Cells, Zheng Cao, Shahriar Koochekpour, Stephen E. Strup, Natasha Kyprianou

Urology Faculty Publications

Dysregulation of transforming growth factor-β1 (TGF-β1) and insulin-like growth factor (IGF) axis has been linked to reactive stroma dynamics in prostate cancer progression. IGF binding protein-3 (IGFBP3) induction is initiated by stroma remodeling and could represent a potential therapeutic target for prostate cancer. In previous studies a lead quinazoline-based Doxazosin® derivative, DZ-50, impaired prostate tumor growth by targeting proteins involved in focal adhesion, anoikis resistance and epithelial-mesenchymal-transition (EMT). This study demonstrates that DZ-50 increased expression of the epithelial marker E-cadherin, and decreased the mesenchymal marker N-cadherin in human prostate cancer cells. In DU-145 cells, the effect of DZ-50 on EMT …

Regulation Of Extracellular Signal-Regulated Kinase By Histone Deacetylase 6, Jheng-Yu Wu

USF Tampa Graduate Theses and Dissertations

Extracellular signal-regulated kinases 1/2 (ERK1/2) are important kinases regulating cell proliferation and cell migration, and have been established as therapeutic targets for cancer treatment. Previously, we found that ERK1 phosphorylates histone deacetylase 6 (HDAC6) to regulate its enzymatic activity. However, whether HDAC6 reciprocally modulates ERK1 activity is unknown. Here, we have discovered that ERK1/2 are acetylated proteins and shown that HDAC6 manipulates ERK1’s kinase activity via deacetylation. We demonstrated that both ERK1 and ERK2 interact with HDAC6 physically. We showed that the acetylation level of GST-ERK1/2 increased in a dose- and time-dependent manner upon treatment with a pan-HDAC inhibitor, Trichostatin …

The Role Of Elevated Hyaluronan-Mediated Motility Receptor (Rhamm/Hmmr) In Ovarian Cancer, Stephanie T. Buttermore

USF Tampa Graduate Theses and Dissertations

Ovarian cancer (OC) has the highest mortality among gynecological cancers. The high mortality is associated with the lack of an accurate screening tool to detect disease in early stage. As a result the majority of OCs are diagnosed in late stage. Further, the molecular events responsible for malignant transformation in the ovary remain poorly understood. Consequently, delineating key molecular players driving OC could help elucidate potential diagnostic, prognostic and therapeutic targets.

Receptor for hyaluronan-mediated motility (RHAMM) belongs to a group of hyaladherins, which share a common ability to bind to hyaluronan (HA). Intracellularly, RHAMM is involved in microtubule spindle assembly …

The Regulation Of Snail: On The Ubiquitin Edge, Qian Yu, Binhua P. Zhou, Yadi Wu

Pharmacology and Nutritional Sciences Faculty Publications

Metastasis accounts for a majority of cancer death. One key feature during metastasis is epithelial-mesenchymal transition (EMT), which is regulated by transcription factors such as Snail and Twist. In non-malignant cells, Snail has a short half-life and is degraded via ubiquitination, but its stability is increased in cancer cell. However, the mechanism by which Snail escapes ubiquitination and degradation remains unknown. Recently, we found that Dub3 is a deubiquinase of Snail. Most importantly, we determined that Dub3 responded to extracellular signals such as IL-6, and that the resultant signaling prevented Snail degradation, and promoted cancer growth, invasion, and migration. In …

Rediscovery Of The Microtubule System In Chlamydomonas, Yi Liu

Dissertations (1934 -)

Extensive studies have revealed the complex mechanisms underlying the roles of the microtubule system in fundamental cellular processes, the severe consequences in development and health resulted from its anomaly, and the irreplaceable therapeutic agents that perturbs this vital yet inherently unstable cytoskeletal system. Most of the concepts derived from a handful of model organisms become dogma of the field despite contrary observations. By overcoming a major limitation of biflagellate green alga Chlamydomonas - the intense autofluorescence common to photosynthetic cells - this dissertation discovered new phenomena of the microtubule system and conceived an invention. The microtubule system of the green …

The Noncanonical Roles Of Two Primordial Molecules In Flagella, Xiaoyan Zhu

Dissertations (1934 -)

Motile cilia and flagella are ancient organelles that eukaryotic organisms today still rely on to thrive in their natural environment. Not surprisingly, accumulated evidence has shown that the intricate motility machinery, the microtubule-based axoneme, is evolutionarily conserved down to the molecular level. This notion is epitomized by the signature axonemal complex, the radial spoke (RS). The RS is part of a control center conferring the high frequency and tightly regulated movement. Key RS proteins discovered in biflagellate green alga, Chlamydomonas reinhardtii, are also generated by nearly all ciliated organisms, including Homo sapiens. Among them are two subunits from primordial protein …

Abnormal Dendritic Maturation Of Developing Cortical Neurons Exposed To Corticotropin Releasing Hormone (Crh): Insights Into Effects Of Prenatal Adversity?, Megan M. Curran, Curt A. Sandman, Elysia Poggi Davis, Laura M. Glynn, Tallie Z. Baram

Psychology: Faculty Scholarship

Corticotropin releasing hormone (CRH) produced by the hypothalamus initiates the hypothalamic-pituitary-adrenal (HPA) axis, which regulates the body’s stress response. CRH levels typically are undetectable in human plasma, but during pregnancy the primate placenta synthesizes and releases large amounts of CRH into both maternal and fetal circulations. Notably, placental CRH synthesis increases in response to maternal stress signals. There is evidence that human fetal exposure to high concentrations of placental CRH is associated with behavioral consequences during infancy and into childhood, however the direct effects on of the peptide on the human brain are unknown. In this study, we used a …

The General Amino Acid Permease Gap1 Is Regulated Differentially By Torc1 Activation And Inhibition, Ray Bowman

D.U.Quark

How does cell signaling in response to extracellular stressors impact the trafficking of membrane proteins? In particular, the TORC1 complex plays a key role in this process and while some details of this system have reported, in a recent Journal of Biological Chemistry publication, Andre’s group has revealed new details of this pathway focusing on the general amino acid permease Gap1 as a model cargo. Andre et al. describe a novel and distinct pathway wherein ubiquitylation and downregulation of Gap1 is regulated not only by amino acid-induced activation of TORC1, but also by numerous sources of TORC1 inhibition and cellular …

Spatiotemporal Regulation Of Atg1 Kinase Activation In Selective Autophagy, Ning Sun

D.U.Quark

Autophagy is a potent intracellular degradation system and thus its activation requires exquisite regulation to maintain cellular homeostasis. Atg1, a serine-threonine protein kinase, is essential in both selective and non-selective autophagy. New findings suggest that in selective autophagy, Atg1 is activated at the vacuole by convergence of two independent recruitment pathways to prevent aberrant autophagy induction.

Hsp70 Conformational Plasticity Allows For Expansive Chaperone Role, Megan Bean

D.U.Quark

The Hsp70 system is an essential component of chaperone activity in many organisms. Hsp70 functions include: protein folding, aggregation prevention, trafficking, and enzyme regulation. Hsp70’s ability to bind such a vast array of substrates suggests wide range of conformational plasticity. By utilizing a single mode optical tweezers technique, Mashaghi1 et al., confirms previous theories Hsp70 binds and stabilizes extended peptide segments but also partially folded and near-native protein.

Plasmodium Falciparum 26s Proteasome Network: A Mystery Solved, Christina Grogan

D.U.Quark

One ofthe most devastating diseases thatthreatens the world population is malaria. The 26S proteasome complex of the malaria parasite Plasmodium falciparum, which was previously unknown, was characterized by the authors through an affinity purification protocol that isolated functional 26S proteasome complexes. This allowed for the identification of subunit composition and PfUSP14, a proteasomeassociated deubiquitinase. This new understanding presents a potential target to disrupt protein regulation in thequest for effective antimalarial strategies.

Autophagy Inhibition In Pain: Role Of A Microrna, Andrea Stevens

D.U.Quark

Neuropathic pain caused by peripheral nerve injury (PNI) leads to the activation and infiltration of microglial cells and to a neuroinflammatory-induced pain state. miRNAs and autophagy are two main factors and/or mechanisms which have the ability to alter the pain state. In this study, miR-195 was shown to be markedly increased after PNI and associated with the pain phenotype. In addition, inhibition of autophagy in vivo led to p62 accumulation, decreased production of LC3, and inhibition of ATG14.

Compartmentalized Camp Responses To Prostaglandin Ep2 Receptor Activation In Human Airway Smooth Muscle Cells, Shailesh R. Agarwal, Kathryn Miyashiro, Htun Latt, Rennolds S. Ostrom, Robert D. Harvey

Pharmacy Faculty Articles and Research

Background and Purpose

Previous studies indicate that prostaglandin EP2 receptors (EP2Rs) selectively couple to adenylyl cyclase type 2 (AC2) in non-lipid raft domains of airway smooth muscle (ASM) cells, where they regulate specific cAMP-dependent responses. The goal of the present study was to identify the cellular microdomains where EP2Rs stimulate cAMP production.

Experimental Approach

FRET-based cAMP biosensors were targeted to different subcellular locations of primary human ASM cells. The Epac2-camps biosensor, which expresses throughout the cell, was used to measure bulk cytoplasmic responses. Epac2-MyrPalm and Epac2-CAAX were used to measure responses associated with lipid raft and non-raft regions of the …