With an estimated 159,900 new cancer cases and 72,200 deaths from cancer predicted to occur this year alone in Canada, the need for new cancer therapies with unique mechanisms of action is urgent. Researchers are finding a promising resource among the ocean’s estimated one to two million structurally diverse microbial species. Compounds derived from marine organisms offer great potential in the fight against cancer; in the past decade, more than 30 natural products from the ocean have entered preclinical and clinical trials as potential treatments for cancer. However, it is often not ecologically or economically feasible to extract the active ingredient by harvesting natural sources in the ocean. Synthetic organic chemistry – where molecules are engineered in the laboratory – serves as an alternative source of these compounds. Inhee Cho is focusing on the synthesis of imbricatine, a chemical originally isolated from the Pacific sea star that shows significant anti-tumour properties. The structural core of imbricatine includes tetrahydroisoquinoline, a molecular structure that is also found in many biologically active agents, including anti-tumour antibiotics and drugs that treat diseases such as asthma, Parkinson’s and other nervous system diseases. Cho is developing an efficient way to synthesize tetrahydroisoquinoine, allowing rapid access to this important class of natural products in order to obtain enough material for biological testing and chemotherapy. Cho’s work may facilitate the discovery of new lead compounds with useful pharmacological properties, potentially leading to new therapies for treating cancer
Research Pillar: Biomedical
Regulation of the Jun Transcription Factors in B Lymphocytes by the NEDD4 Family E3 Ubiquitin Ligase, Itch
Ubiquitin is a small protein found in all cells containing a nucleus. A key function for this protein is ubiquitylation, the process by which ubiquitin attaches to target proteins to “mark” them for degradation (breaking down) and removal from the cell. Ubiquitylation is an important process for maintaining proper levels of cellular proteins and removing mis-folded proteins to ensure proper cellular function and to prevent disease. E3 Ub ligases are important regulators of the ubiquitylation process because they select the specific proteins (substrates) that are to be degraded. Itch is an E3 Ub ligase that is important in the immune system, as mice deficient in Itch (Itchy mice) develop a fatal autoimmune-like disease. The Jun transcription factors, c-Jun and JunB, are found to be deregulated in the T cells of these mice, and this is believed to contribute to the disease. These proteins are also important for the proper function of B cells and their deregulation has been implicated in some B cell cancers, such as Hodgkin lymphoma. Joel Pearson is determining whether Itch also regulates the Jun proteins in B cells, and how this may contribute to the autoimmune-like disease of Itchy mice. He is also investigating whether Itch regulates the Jun proteins in B and T cell lymphomas where these proteins are expressed at unusually high levels. His hypothesis is that Itch is an important regulator of the Jun proteins in B cells. Furthermore, he believes that Itch is also an important regulator of the Jun proteins in B and T cell lymphomas where these proteins are over-expressed. Understanding how the Jun proteins are regulated in these cells is important for understanding how the autoimmune-like disease of Itch-deficient mice may arise. Deregulation of the Jun proteins also contributes to the pathogenesis of some types of B and T cell lymphomas. Because of this, understanding how they are regulated is important for understanding how these cancers arise and persist. It could also lead to the development of novel ways to treat these cancers.
Integrating gene expression data, interaction network information and evolutionary analysis to investigate mammalian innate immunity at the systems level
The immune response is the set of defenses our bodies mount to counter harmful microbes. The innate immune response is our first line of defense, providing protection until the adaptive immune response is activated. Unfortunately, the innate immune response can also be a double-edged sword. It can spin out of control and cause an overwhelming immune response called sepsis, which is responsible for 200,000 deaths every year in the US. The innate immune response is initiated and regulated by complex signalling pathways of genes in our cells. These pathways identify which type of microbe is invading (bacteria or viruses, for example) and mounts appropriate responses. Dr. David Lynn is investigating the genes involved in the innate immune response, how they are turned on and off in particular infections, and what goes wrong in cases of sepsis. This work generates vast quantities of data, requiring computer-based approaches (bioinformatics) to understand and handle such large datasets. Lynn’s work integrates gene expression data with information about how genes and proteins are interconnected in our cells in signalling networks or pathways – providing new information about gene interconnections influence their regulation. He is also investigating the same networks and pathways in other species such as mouse and cow, determining the differences and similarities in their innate immune response. Lynn’s work will help identify potential therapeutic or drug targets that could help safely boost the immune response. It will also highlight cases where important immunological differences make animal models unsuitable for research on human immunity.
Pathogenomics of innate immunity: analysis of the roles of TNIP1, DUSP16, and TANK in toll-like receptor signalling, innate immunity and inflammation, using novel gene-knockout mice
When disease-causing microorganisms breach the body’s external defences, protective mechanisms of innate immunity are rapidly activated. These are essential to control and clear the infection, but can also contribute to tissue damage. Uncontrolled or inappropriate activation of innate immunity can cause chronic inflammatory disorders, such as arthritis, or result in a highly-dangerous state of acute inflammation, known as sepsis. Thus, a detailed knowledge of innate immunity is critical for understanding the mechanisms regulating inflammation and the causes of human inflammatory diseases. It is also essential if we are to develop therapies that artificially boost innate immunity to cure infections, without inducing damaging inflammation. Activation of innate immunity is critically dependent on several classes of receptor-proteins, which detect infections by selectively binding microbial compounds. Toll-like receptors (TLRs) are one of the most important classes of such proteins, activating a cascade of events that is an essential part of the early phases of innate immune response. Previous research has identified a set of genes, believed to be important regulators of TLR signalling, innate immunity and inflammation. As part of a large, multinational research program, Dr. Anastasiya Nyzhnyk is focusing on three of these genes: TNIP1, DUSP16 and TANK. Using mouse models and human cell lines, she is analyzing how the inactivation of these genes affects TLR signalling, and studying the resulting molecular, cellular, and physiological effects. Her work is expected to expand knowledge about early immune responses to infection, and may lead to a better understanding of the causes of inflammatory diseases and suggest new strategies for their therapy
Novel characterization of a G-protein coupled receptor, Autocrine Motility Factor Receptor (AMFR): an endoplasmic reticulum-localized E3 ubiquitin ligase
The endoplasmic reticulum is a membrane network within cells involved in the synthesis, modification, and transport of cellular materials. Endoplasmic Reticulum Associated Protein Degradation (ERAD) is a cellular process that identifies unneeded or misfolded proteins of the endoplasmic reticulum and modifies the protein by attaching to it a ubiquitin protein. This ubiquitination process serves to mark the protein for destruction – a key process that helps prevent a range of diseases. Autocrine motility factor receptor (AMFR) is a transmembrane protein expressed on the cell surface and in a smooth subdomain of the endoplasmic reticulum (SER). AMFR has a critical function in the ubiquitination process, binding to the regulatory protein autocrine motility factor (AMF). Overexpression of AMF and AMFR occurs in a number of malignancies and participates in cancer cell migration during cancer progression and metastasis. It has been observed that AMF is secreted by tumour cells and acts as a protein messenger to other cells. However, its mechanisms remain unknown. Maria Abramow-Newerly is determining the signalling pathways used by AFMR following its binding to AMF, working to identify critical proteins and factors that may all tightly regulate AMFR expression and distribution within normal and cancer cell lines. In particular, she is focusing on characterizing AMFR as a G-protein coupled receptor, a family of proteins that serve as important drug targets for a number of diseases. Abramow-Newerly’s studies may contribute to the future design of drugs that specifically target components in the AMFR-signalling pathway to reduce cancer cell migration and metastasis
Formation, stabilization, and dynamic modulation of GABAergic inhibitory synapses in the central nervous system
In the central nervous system (CNS), the chemical synapse is the major site of communication between neurons (nerve cells). There are two main types of synapses in the CNS: excitatory glutamate synapses and inhibitory gamma-aminobutyric acid (GABA) synapses. Dysfunction of GABA synapses has been identified in disorders such as autism, schizophrenia, and depression. GABA synapses are also the main targets for drugs to treat epilepsy and anxiety. The protein neuroligin is a molecule that directs a neuron to form a synapse at the place where it comes in contact with another neuron. A specific type of neuroligin, Neuroligin-2, builds GABA synapses. However, little is known about why and how Neuroligin-2 is specific for building GABA synapses. Frederick Dobie was previously funded by MSFHR for his research in protein transport in neurons. He is now studying proteins involved in synaptogenesis (the process of building a synapse). To better understand how GABA synapses are formed, he is looking at regions of Neuroligin-2 that are important for this function. He is also studying how GABA synapses can change over time, responding to the specific needs of the neuron to fit into a fully-functioning brain. He is watching the growth and maturation of synapses over a period of several days, observing in real-time the strikingly dynamic appearance, disappearance, and movement of synapses. By understanding the biology underlying GABA synapses, Dobie hopes his work will ultimately lead to the advancement of therapies for a wide range of debilitating developmental, neurological, and psychiatric disorders.
OGC as a link between mitochondrial function, aging and diabetes
Marco Gallo is using Caenorhabditis elegans (a small worm) as a model organism to determine how mitochondrial 2-oxoglutarate carrier (OGC) affects aging and insulin signalling. He is studying how this protein interacts with the insulin pathway, and how it affects the development and function of mitochondria, which serve as the cell’s energy source. The proposed mechanism by which OGC is involved in the occurrence of diabetes is by modulating insulin signalling (the cascade of molecular events that result in insulin production). A related version of this protein (B0432.4) is also found in C. elegans. In worms, suppression of this protein resulted in a 20 per cent increase in their average and maximum life-span & in changes in the levels of insulin secretion. Gallo’s research aims to identify the mechanisms that mediate the interaction between OGC and insulin signalling. He is addressing this question with work on C. elegans, mouse & human cell lines. This work could shed more light on the changes that occur in the mitochondria and lead to metabolic diseases, with an emphasis on diabetes.
Regulation of T Cell Development, Function and Transformation by Interleukin-7.
Immune disorders – such as immunodeficiencies, leukemia and lymphoma, autoimmunity, and allergy – are significant health problems. For example, every year 5,600 Canadians people die of cancers of the immune system, such as leukemia and lymphoma, and these cancers account for 42% of all cancers in children. Current treatments for these cancers, such as chemotherapy and radiation therapy, have significant shortcomings. To improve recovery rates and reduce unwanted side effects, researchers need to develop new, specifically targeted treatment approaches. Treating diseases with few side effects requires knowing the signals involved in disease development. Dr. Ninan Abraham is focusing his research on understanding how a cytokine called interleukin-7 (IL-7) regulates immune cells by interacting with proteins to trigger biochemical pathways that control normal cell development and function. IL-7 is an essential growth factor that promotes the development of T cells and memory T cells, which are both essential for the body’s response to pathogens that lead to disease or infection. Being able to enhance development or survival of T cells by manipulating IL-7 could lead to the creation of more effective vaccines to boost the body’s immune response to disease. Conversely, since over-expression of IL-7 is associated with several forms of human T cell lymphoma, being able to limit this cytokine’s activity could also be important. By identifying how IL-7 promotes the development or survival of T cells and memory T cells, Abraham hopes for new strategies for treating these cancers and enhancing vaccines for long-term immunity.
Mechanisms of topical calcipotriol mediated tolerance induction
Autoimmune diseases such as type 1 diabetes, lupus, and multiple sclerosis are a serious health issue in North America, affecting more than 22 million people in the US alone. Unfortunately, current treatment options for individuals suffering from autoimmunity are limited, and patients are often faced with the prospect of life-long drug regimens designed to suppress their immune systems. While effectively managing autoimmune diseases, these drugs can also hamper the body’s ability to defend itself against infection and cancer, substantially reducing a patient’s quality of life. T regulatory cells (Tregs) are a class of immune cell that prevent the immune system from attacking the body. Because Tregs can prevent autoimmune disease, many attempts have been made at designing methods to generate them. As of yet, no practical and reliable means of producing Tregs has been achieved. Previous research demonstrates that Vitamin D may play a role in the Treg production process. Paxton Bach is investigating whether applying Vitamin D to the skin can be used to generate Tregs, and early results are promising. Ultimately, this research could lead to more effective, less invasive treatments for individuals living with autoimmune diseases around the world.
Determination of cleavage site specificity of matrix metalloproteases by assay of a peptide library generated by enzymatic digest of a complete or partial proteome
Mass spectrometry is a technique for separating and identifying molecules based on mass. It’s an important tool in proteomic investigations, the analysis of the whole set of proteins expressed in a cell. Recent advances in mass spectrometry have enabled the identification of thousands of unknown nd uncharacterized proteins. Many of these proteins are proteases, enzymes responsible for splitting specific peptide bonds (primary links of protein structures). Patrick Beaudette is studying a protease family known as matrix metalloproteases (MMPs). MMPs regulate a variety of cell processes, from the degradation of structural proteins to the activation and inactivation of cell signaling pathways. Proteins proteolytically processed under these circumstances can have implications in a variety of disease symptoms, ranging from inflammation to tumor growth. Beaudette’s research focuses on identifying the substrates (molecules upon which enzymes act) that a particular MMP protein splits, and the mechanism by which it locates these substrates within the cell. The research may lead to a fuller understanding of the function of the MMP family of enzyes and the role it plays within a cell. The findings could contribute to the design of inhibitors for MMPs for use in therapy of cancer and other conditions.