Life Sciences Commons^™

Structural Basis For Chloroperoxidase Catalyzed Enantioselective Epoxidations And Mechanisms Of Selected Anticancer Drug Induced Apoptosis, Yongjian Guo

FIU Electronic Theses and Dissertations

Chloroperoxidase (CPO), a member of the heme peroxidase family, has diverse catalytic activities toward a broad range of substrates. In addition to catalyzing halogenation reactions involved in the biosynthesis of halogen-containing compounds, CPO also catalyzes reactions typical of traditional heme peroxidases, catalases, and cytochrome P450 enzymes. Despite the powerful and versatile catalytic activity of CPO, its applications have been thwarted by the difficulty in regenerating the active enzyme and substrate (peroxide) induced protein inactivation. To overcome these shorting comings of the protein, we investigate the fabrication and characterization of chloroperoxidase (CPO) and glucose oxidase (GOx) on the surface of MGO. …

Dual Role Of Rin1 In Cancer Cell Behavior: Is Cortactin A New Rin1-Interacting Partner?, Wei Zhang

FIU Electronic Theses and Dissertations

Growth factors play an essential role in abnormalities in both intracellular trafficking and signal transduction pathways responsible in normal and cancer cells. Growth factors, such as epidermal growth factor, represent a main course on the activation of mitogenic signal that contribute to the mitogen activated protein kinase (MAPK) pathway affecting cell proliferation, which is driven by Ras GTPases. However, it also induces a profound morphological change by reorganization actin and other cytoskeleton proteins, which are driven by other GTPases (i.e., Rho and Rac). Ras interference 1 (Rin1) is a key cytosolic protein, that regulates both membrane trafficking and signaling pathways …

The Role Of Inositol Polyphosphate-4-Phosphatase Type Ii B (Inpp4b) In Obese Models And Endocrine Cancers, Manqi Zhang

FIU Electronic Theses and Dissertations

INPP4B is a dual-specificity phosphatase and a tumor suppressor in prostate and breast cancers. Progression of the prostate and breast cancers depends on the androgen receptor (AR) or estrogen receptor alpha (ERα) signaling, respectively. In this work we demonstrated that INPP4B reprograms ERα transcriptional activity in breast cancer. INPP4B maintains expression and protein levels of progesterone receptor (PR), an ERα direct target gene required for mammary gland development. Consistently we demonstrated that Inpp4b knockout severely impairs lateral branching in the mammary gland of maturing virgin females. In advanced prostate cancer, activation and transcriptional reprogramming of AR frequently coincides with the …

Regulation Of Telomerase Activity By Rab5 Guanine Nucleotide Exchange Factors, Patric J. Hambleton

FIU Electronic Theses and Dissertations

Many cancerous cells display abnormalities in the signal transduction pathways responsible for responding to extracellular growth factors. Growth factors, such as insulin-like growth factor I, represent a major class of mitogenic ligands that can initiate the mitogen activated protein kinase (MAPK) pathway. The role of the MAPK pathway in transducing growth signals to the interior of the cell and subsequently stimulating cell growth and proliferation is highlighted by the fact that roughly one quarter of all human tumors contain mutant forms of Ras proteins. Ras interference 1 (Rin1) is involved in key steps of receptor mediated endocytosis and can potentially …

Evolutionary Expansions And Neofunctionalization Of Ionotropic Glutamate Receptors In Cnidaria, Ellen G. Dow

FIU Electronic Theses and Dissertations

Reef ecosystems are composed of a variety of organisms, transient species of fish and invertebrates, microscopic bacteria and viruses, and structural organisms that build the living foundation, coral. Sessile cnidarians, corals and anemones, interpret dynamic environments of organisms and abiotic factors through a molecular interface. Recognition of foreign molecules occurs through innate immunity via receptors identifying conserved molecular patterns. Similarly, chemosensory receptors monitor the environment through specific ligands. Chemosensory receptors include ionotropic glutamate receptors (iGluRs), transmembrane ion channels involved in chemical sensing and neural signal transduction. Recently, an iGluR homolog was implicated in cnidarian immunological resistance to recurrent infections of …

Superoxide Dismutase C Modulates Macropinocytosis And Phagocytosis In Dictyostelium Discoideum, Cong Gu

FIU Electronic Theses and Dissertations

Macropinocytosis and phagocytosis, two actin-dependent and clathrin independent events of endocytosis, enable the cells such as macrophages and neutrophils to either internalize pathogens and initiates the human innate immune response or serve as a direct entry route for productive infection of pathogen. Dictyostelium discoideum, soil-living amoeba, a unicellular eukaryote that could professionally internalize fluid phase or particles several folds more than that of macrophages and neutrophils. Additionally, multiple key signaling pathways are conserved between Dictyostelium and mammalian cells, including pathways affecting small GTPases Ras and Rac and their downstream effectors, and F-Actin remodeling. All these traits makes Dictyostelium an …

Impact Of San-Mediated Signaling On Glioblastoma And Neuroblastoma Metabolism, Monica Rodriguez Silva

FIU Electronic Theses and Dissertations

Glioblastoma (GBM) is the most common and aggressive type of brain cancer, with an average life expectancy of 15 months. The standard of care for GBM, surgery accompanied by radiation and chemotherapy (temozolomide-TMZ), has not changed in over 10 years illustrating the need for new and efficacious treatments. Therefore, it is imperative to improve our knowledge of GBM physiology to understand the mechanisms driving recurrence and chemoresistance so that more effective therapeutic options can be developed. Mitochondria-cell communication is key to monitor and maintain both mitochondrial and cellular health, and signaling events on the outer mitochondrial membrane (OMM) have emerged …

Id3, Estrogenic Chemicals, And The Pathogenesis Of Tumor-Like Proliferative Vascular Lesions, Vincent E. Avecilla

FIU Electronic Theses and Dissertations

Tumor-like proliferative vascular lesions manifest in several diseases such as peripheral arterial disease (PAD) and atherosclerosis (AS) after arterial injury. The cause of the vascular cell dysfunction in PAD patients is not known. Our recent novel discovery shows that inhibitor of differentiation 3 (ID3) is highly expressed in intimal lesions of clinical vascular disease samples. The central hypothesis of our study is: estrogenic chemical induced dysregulation of ID3 target genes is involved in the development of vascular disease. NHANES data analysis demonstrated higher geometric levels of all 6 PCB congeners in both PAD diagnosed participants and participants at risk of …

Transgneic Endothelin 3 Regulates Murine Pigment Production And Coat Color, Javier Pino

FIU Electronic Theses and Dissertations

Pigmentation plays a protective role against damage caused by ultraviolet (UV) irradiation. Humans with fair skin and light hair have a higher susceptibility to UV-induced DNA damage that can lead to the development of skin cancers. The melanocytes found in the skin and hair follicles depend on different signaling molecules for their proper development and pigment production. α-Melanocyte Stimulating Hormone (α-msh) binds to the Melanocortin 1 receptor (Mc1r) to regulate pigment production and the switch between eumelanin and pheomelanin. Lethal yellow mice (A^y) overexpress the agouti signaling protein, which inhibits the binding of α-msh, resulting in a yellow …

Regulation Of Adipocyte Differentiation And Metabolism: Rab5-Guanine Nucleotide Exchange Factors And Methylglyoxal, Praew Chantarasinlapin

FIU Electronic Theses and Dissertations

Internalization and trafficking of ligand-receptor complex rely on a particular set of proteins, e.g. small GTPase protein Rab5 and its activators called guanine nucleotide exchange factors. Rab5-activating protein 6 (RAP6), a Vps9-containing protein, may participate in Rab5-mediated insulin signaling and receptor trafficking. A dicarbonyl compound methylglyoxal was found to alter insulin signaling in preadipocytes. This dissertation aimed to investigate the association of RAP6 activity on 3T3-L1 preadipocyte differentiation and those driven by methylglyoxal. Overexpression of RAP6 inhibited preadipocyte differentiation, Ser473-phosphorylation of Akt1, and expression of adipogenic marker PPARγ, but not C/EBPα. Methylglyoxal (10 µM) increased preadipocyte differentiation, proliferation and expression …

The Effects Of Artemisia Derived Natural Products On Adipogenesis, Steven Abood

FIU Electronic Theses and Dissertations

For the first time in human history, more people worldwide suffer from obesity than are undernourished. Numerous health complications are associated with obesity including cardiovascular disease, Type 2 Diabetes, cancers of reproductive tissues, stroke, depression, anxiety disorders, and Alzheimer’s disease. A deeper understanding of the anti-adipogenic effects and mechanism of action of sesquiterpene lactones may have pharmacological import in the continuing search for therapeutic modalities to ameliorate the effects of this global obesity epidemic.

Dehydroleucodine (DhL), 11,13-dihydro-dehydroleucodine (DH-DhL), and dehydroparashin-B (DhP), sesquiterpene lactones extracted from or derived from compounds extracted from Artemisia douglasiana, were investigated for their anti-adipogenic effects …

Regulation Of Particle Uptake By Pp2a/B56 And Lkb1 In Dictyostelium Discoideum, Mujataba Rahiman Sharief

FIU Electronic Theses and Dissertations

Dictyostelium discoideum is a soil dwelling amoeba which has been widely used as a model organism to study cellular processes such as signal transduction, chemotaxis, endocytosis and exocytosis. The process of phagocytosis in Dicytostelium is largely comparable to that of neutrophils and macrophages in the mammalian system. Neutrophils and macrophages are cells of the innate immune system and they engulf infectious bacteria through phagocytosis. Dictyostelium cells uptake yeast and bacteria for their nutrition through phagocytosis, which is an actin dependent mechanism and is a target of multiple signaling inputs. Recent studies have uncovered different proteins involved in the signaling of …

The Role Of Endothelin 3 In Melanoma Progression And Metastasis, Nikeisha L. Chin

FIU Electronic Theses and Dissertations

Endothelin receptor b (Ednrb) and its ligand Endothelin 3 (Edn3) have been implicated in melanoma. Several studies have shown an upregulation of EDNRB and EDN3 at both the protein and mRNA levels, as melanoma becomes more aggressive. This study investigated the putative role played by Edn3 over-expression in melanoma progression and angiogenesis in vivo. We crossed Tg(Grm1)Epv transgenic mice that aberrantly express metabotropic glutamate receptor1 under the Dopachrome tautomerase promoter, leading to spontaneous melanocytic lesions in the ears and tails that do not metastasize, with transgenics that overexpress Edn3 under the Keratin 5 promoter ( …

Intracellular Signaling And Trafficking In Cancer: Role Of Rab5-Gtpase In Migration And Invasion Of Breast Cells, Nicole Porther

FIU Electronic Theses and Dissertations

Metastasis is characterized pathologically by uncontrolled cell invasion, proliferation, migration and angiogenesis. Steroid hormones, such as estrogen, and growth factors, which include insulin growth factor I/II (IGF-1/IGF-2) therapy has been associated with most if not all of the features of metastasis. It has been determined that IGF-1 increases cell survival of cancer cells and potentiate the effect of E2 and other ligand growth factors on breast cancer cells. However not much information is available that comprehensively expounds on the roles of insulin growth factor receptor (IGFR) and Rab GTPases may play in breast cancer. The latter, Rab GTPases, are small …

Redox Regulation Of Ras Proteins In Dictyostelium Discoideum, Boris Castillo Chabeco

FIU Electronic Theses and Dissertations

Reactive oxygen species are a normal consequence of life in an aerobic environment. However when they deviate from the narrow permissible range in cells, oxidative damage can occur. Dictyostelium discoideum is a model organism ideal for the study of cell signaling events such as those affected by oxidative stress. It was previously shown that Ras signaling in Dictyostelium is affected by genetic inactivation of the antioxidant enzyme Superoxide dismutase C (SodC) and in vitro data suggests that the NKCD motif of Ras is the redox target of superoxide.

The main objective of this project was to determine the mechanism of …

Theoretical Investigation Of Intra- And Inter-Cellular Spatiotemporal Calcium Patterns In Microcirculation, Jaimit B. Parikh

FIU Electronic Theses and Dissertations

Microcirculatory vessels are lined by endothelial cells (ECs) which are surrounded by a single or multiple layer of smooth muscle cells (SMCs). Spontaneous and agonist induced spatiotemporal calcium (Ca²⁺) events are generated in ECs and SMCs, and regulated by complex bi-directional signaling between the two layers which ultimately determines the vessel tone. The contractile state of microcirculatory vessels is an important factor in the determination of vascular resistance, blood flow and blood pressure. This dissertation presents theoretical insights into some of the important and currently unresolved phenomena in microvascular tone regulation. Compartmental and continuum models of isolated EC …

Understanding Ten-Eleven Translocation-2 In Hematological And Nervous Systems, Feng Pan

FIU Electronic Theses and Dissertations

I proposed the study of two distinct aspects of Ten-Eleven Translocation 2 (TET2) protein for understanding specific functions in different body systems.

In Part I, I characterized the molecular mechanisms of Tet2 in the hematological system. As the second member of Ten-Eleven Translocation protein family, TET2 is frequently mutated in leukemic patients. Previous studies have shown that the TET2 mutations frequently occur in 20% myelodysplastic syndrome/myeloproliferative neoplasm (MDS/MPN), 10% T-cell lymphoma leukemia and 2% B-cell lymphoma leukemia. Genetic mouse models also display distinct phenotypes of various types of hematological malignancies. I performed 5-hydroxymethylcytosine (5hmC) chromatin immunoprecipitation sequencing (ChIP-Seq) and RNA …

Design And Synthesis Of 4-N-Alkanoyl And 4-N-Alkyl Gemcitabine Analogues Suitable For Positron Emission Tomography, Jesse E. Pulido

FIU Electronic Theses and Dissertations

Gemcitabine is a highly potent chemotherapeutic nucleoside agent used in the treatment of several cancers and solid tumors. However, it is therapeutically limitated because of toxicity to normal cells and its rapid intracellular deamination by cytidine deaminase into the inactive uracil derivative. Modification at the 4-(N) position of gemcitabine's exocyclic amine to an -amide functionality is a well reported prodrug strategy which has been that confers a resistance to intracellular deamination while also altering pharmacokinetics of the parent drug. Coupling of gemcitabine to carboxylic acids with varying terminal moieties afforded the 4-N-alkanoylgemcitabines whereas reaction of 4-N …

Aspects Of The Innate Immune System In The Caribbean Octocoral Swiftia Exserta, Lorenzo P. Menzel

FIU Electronic Theses and Dissertations

The immune systems of cnidaria are important to study for two reasons: to gain a better understanding of the evolution of immune responses, and to provide a basis to partially redress the precipitous world-wide die-offs of reef corals, some of which have been attributed to diseases and stress. Many immune responses share ancient evolutionary origins and are common across many taxa.

Using Swiftia exserta, an azooxanthellate ahermatypic local octocoral, as a proxy model organism to study aspects of innate immunity in corals and cnidaria allows us to address both of the reasons listed above while not using endangered species. …