Maddalena Allegretta, M.A.
Mechanisms for evaluating DNA regulatory element interactions abstract
Advisor: James Russo
Felix S. Baier, M.A.
The Molecular and Cellular Basis of Invertebrate Host Preference abstract
Advisor: Leslie Vosshall
Raevti Bole, M.A.
A relationship in the balance: how microglia and monocytes contribute to the development of neuropathic pain abstract
Advisor: Joachim Scholz
Jason H. Buchel, M.A.
Epigenetics, Neuroplasticity and Schizophrenia abstract
Advisor: Marija Kundakovic
Veronica Castro, M.A.
High-Throughput Loss of Function Screening Identifies a Synthetic Lethal Pair In a Breast Cancer Cell Model abstract
Advisor: Jose Silva
James V. Coleman, M.A.
Proteomic Biomarker Discovery and Validation abstract
Advisor: Lewis Brown
Monica S. Diosdado, M.A.
MicroRNAs as Key Mediators between Inflammation and Cancer abstract
Advisor: James Russo
Eric Greenwald, M.A.
Eukaryotic Homologous Recombination Repair: A Dynamic Cast of Characters abstract
Advisor: Eric Greene
Philip L.A. Hahn, M.A.
Mitochondrial Diseases, Treatments, and FDA Orphan Legislation abstract
Advisor: Ron Guido
Alexander A. Kalin, M.A.
Diminishing the Side Effects of Cancer Treatment by Improving Treatment Delivery abstract
Advisor: Lily Khidr
Noopur V. Khobrekar, M.A.
Wilms tumor X An X-linked tumor suppressor that acts through protein-protein interactions abstract
Advisor: Carol Prives
Caroline J. Kim, M.A. 2012
Diagnostic Tools and Treatments of Major Psychiatric Disorders abstract
Advisor: Ron Guido
Jonathan Y. Kim, M.A.
Structure Biology of Membrane Proteins: Insights from Four Recent Examples abstract
Advisor: Filippo Mancia
Katerina Leon, M.A.
Perspectives on the applications of viral vectors in gene therapy abstract
Advisor: Jairo Mendez Rico
James L. Lynch, M.A.
Tissue Engineering of the Small Intestine abstract
Advisor: Hayden Huang
Jacqueline A. McCray, M.A.
Achieving Personalized Medicine through Pharmacogenetics: The Future of Healthcare abstract
Advisor: Wendy Chung
Akanksha Nayak, M.A.
Hereditary Non-Polyposis Colon Cancer: Important Molecular Causes and Therapies abstract
Advisor: Carol Prives
Sara Nik, M.A.
The Role of Primary Cilia in Neuronal Development and Disease abstract
Advisor: Carlo Iomini
Brittany J. Perry, M.A.
Searching for Rare Mutations in Patients with Congenital Anomalies of the Kidney and Urinary Tract abstract
Advisors: Ali Gharavi and Ron Guido
Aidan S. Quinn, M.A.
Molecular Signatures in Breast Cancer: Past, Present and Future abstract
Advisors: Carlos Cordon-Cardo
Ziwei Song, M.A.
Current treatment modalities and novel gene therapy approaches in Type 2 Diabetes Mellitus abstract
Advisor: Ira Tabas
Lauren C. Strazzulla, M.A.
Behind the switchboard: the role of Rho GTPase control of cellular processes and cancer progression abstract
Advisor: Angel Pellicer
Chen-Hsien Su, M.A.
Current Ex-vivo Gene Therapy Technology and Future Developments abstract
Advisor: Stephen Tsang
Mansi Vasistha, M.A.
Tissue Engineering of Skin: Scope and Future abstract
Advisor: Qing-Qing Qiu
Nengyi Zhou, M.A.
Distinct Synthetic Lethal Interactions in Various Mutated Tumors abstract
Advisor: Suresh Jhanwar
Mechanisms for evaluating DNA regulatory element interactions
Maddalena Allegretta, M.A. 2012
The complexity of the human genome was only partially elucidated by the completion of the Human Genome Project in 2003. A complete understanding of the role of DNA regulatory elements as a means of transcriptional and structural control is imperative to comprehending the mechanisms underlying disease and development. Noncoding DNA is believed to contain transcriptional regulatory elements, interacting with a variety of proteins comprising a gene regulatory network in cells. Noncoding DNA predominates in the genome, with only 1.5% of the three billion base pairs of the human genome coding for proteins. Knowledge as to how these genomic locations bind proteins and affect gene expression necessitates a reproducible method of studying these chromosomal interactions in vivo. The following will provide a survey of past and present methodology that has been used in the study of the specific interactions between proteins and nucleic acids.
The Molecular and Cellular Basis of Invertebrate Host Preference
Felix S. Baier, M.A. 2012
How behavior is encoded on the level of genes and neural circuits is increasingly being understood, but little is known about the mechanistic basis of behavioral evolution. Parasitic invertebrates depend on hosts for nourishment and reproduction, and have evolved mechanisms for their recognition. Host preference has long been recognized as one of the drivers of global biodiversity, and knowledge of the molecular and cellular basis of evolutionary shifts in host preference could lead to fundamental insights into the diversification of life.
Also, many anthropophilic invertebrates carry deadly pathogens. Disrupting parasite host preference for humans may be an efficient tool to leverage global health problems. Knowledge of the molecular basis of insect host preference has thus also immediate medical relevance.
Here, I summarize our current state of knowledge of the molecular and cellular basis of invertebrate host preference. I discuss the number and chromosomal location of host preference loci, and the few cases where host preference genes have been identified. I comment on sex linkage of host preference loci in butterflies and what this means in evolutionary terms. I also talk about the cellular basis of host preference divergence, and if most changes involved in host preference occur at the peripheral or more central stage of the pathway controlling host preference. Eventually, I briefly mention non-genetic factors that influence host preference.
A relationship in the balance: how microglia and monocytes contribute to the development of neuropathic pain
Raevti Bole, M.A. 2012
Neuropathic pain differs from physiological pain in that it is characterized by reduced pain thresholds, as well as the perception of pain in the absence of a noxious stimulus. While it usually arises from a direct insult to the somatosensory system, there is a contributory immunological component in the form of microglia and monocyte activation in response to the initial nerve injury. These cells are intimately involved in the development of neuropathic pain; however there are still some unresolved areas of knowledge regarding the relative contribution of each cell type in the central nervous system, which has traditionally been considered sequestered from the immune system. This paper seeks to explore the literature on microglial and monocyte activation in the spinal cord following peripheral nerve injury, with a view to understanding further avenues for the effective treatment of neuropathic pain.
Epigenetics, Neuroplasticity and Schizophrenia
Jason H. Buchel, M.A. 2012
Epigenetics is a recently emerging field that studies changes in gene expression that occur without any modifications to a DNA sequence. DNA methylation is the best established epigenetic mechanism; it is a process where methyl groups are attached to DNA and in effect typically repress transcription of a gene. Epigenetics is suggested to play a role in a multitude of processes that deal with the central nervous system (CNS), including neuroplasticity. Plasticity occurs when brain maps and connections between neurons are modified, such as during learning and memory where synapses and the connections between neurons strengthen. Previous studies have demonstrated that altering DNA methylation patterns are correlated with neuroplasticity abnormalities that may lead to varying degrees of cognitive impairment. These cognitive impairments, including poorer spatial and working memory, are also commonly observed in schizophrenia. Interestingly, epigenetic processes have also been implicated in the pathophysiology of schizophrenia. Therefore, it is plausible that the pathology of schizophrenia involves neuroplasticity deficits that occur due to epigenetic dysregulation. In gaining a better understanding of this link between epigenetics, neuroplasticity, and schizophrenia - new therapies can be explored that aim to target the epigenetic machinery possibly connected to the cognitive dysfunction observed in schizophrenic patients. This new approach to understanding schizophrenia could potentially revolutionize the way the disease is treated, as current treatments fail to target the cognitive impairments observed in patients.
High-Throughput Loss of Function Screening Identifies a Synthetic Lethal Pair In a Breast Cancer Cell Model
Veronica Castro, M.A. 2012
A big drawback in cancer therapeutics has been the identification of drug targets that would lead to the selective killing of cancer cells, leaving normal ones unharmed. In the last decade, new therapies based on the specific molecular changes that drive tumorigenesis have emerged, giving rise to an era of personalized medicine. Unfortunately, these targeted therapies fail to provide a long term-cure, and have only proven to delay the progression of the disease. Thus, new strategies are necessary to find better cellular targets for more efficient and tailored therapy.
Cancer cells undergo a process in which multiple regulatory networks are rearranged in order to adapt to the specific genomic alterations present in the cell. Even though all tumors share common characteristics such as limitless potential for replication, cell death evasion, or self-sufficiency in growth signals; each cancer cell is characterized by its genomic abnormality. Thus, it is feasible to use genetic approaches to identify targets that will kill cancer cells based on their unique genomic profile. In recent years, the concept of synthetic lethal interactions has become a promising alternative approach to find genetic synthetic partners with cancer cells carrying specific mutations.
About 20-40% of all breast tumors show overexpression of the tyrosine kinase receptor ErbB2. Even though targeted therapies such as the monoclonal antibody Trastuzumab and the small tyrosine kinase inhibitor Lapatinib successfully target ErbB2 overexpressing cells, the majority of patients develop resistance to these drugs within a year of treatment. Thus, identifying new tumor targets that act as lethal partners with this alteration can benefit patients whose current method of treatment has lost efficacy.
Proteomic Biomarker Discovery and Validation
James V. Coleman, M.A. 2012
Many diseases have both environmental and genetic components that shape their etiology. The interaction of these and other variables can lead to diseases that have similar physical presentation but a divergent molecular origin. Additionally, the gradual accumulation of signs and mild nature of initial symptoms can be an impediment to early diagnosis. Attempts are being made to find and validate biological disease markers that permit a better understanding of the disease state and provide pre-symptomatic diagnosis. Despite the large amounts of money being spent on proteomic research, few novel protein biomarkers for cancer are gaining FDA approval. Provided within is a review of proteomic methods for biomarker discovery and validation, examined through the lens of solid tumor diagnosis from serum or plasma. A critical review of platform-inherent analytical difficulties is provided, with attention paid to those that create proteomic “blind spots” or otherwise bias proteome coverage. Included is an examination of current hurdles in the pipeline; particular emphasis is given to a technical review of pre-analytical variation sources, as well as study design considerations. Also examined are the potentials of direct serum profiling and so-called “proteomic footprinting” as methods by which biomarkers can be discovered without extensive knowledge of a tumor’s pathophysiology. The review supports the dedicated exploration of the peptidome and glycoproteome as pools of exported molecules that are known to show aberrations in the disease state and that may have promise as serum markers. Evidence is also presented for the use of multiple reaction monitoring and aptamer arrays as validation alternatives to immunoassay methods, as these may lower validation costs, improve throughput, and permit the large-scale examination of many more candidate markers than is presently feasible. Taken together, the examination of current impediments provides clear evidence that the exploration of sub-proteomes and the utilization of new technologies are virtual prerequisites for the translation of candidate markers into clinically relevant diagnostic tools.
MicroRNAs as Key Mediators between Inflammation and Cancer
Monica S. Diosdado, M.A. 2012
Inflammation plays a role in tumor initiation, progression, and metastasis. Clinical, molecular, and epidemiological studies have demonstrated a connection between inflammation and various types of cancer. Important mediators of cancer that link it with inflammation are specific microRNAs, NF-κB, reactive oxygen and nitrogen species, cytokines, and prostaglandin. These associations are involved in cell proliferation, cell death, cellular senescence, DNA mutation rates, DNA methylation and angiogenesis, resulting in a tumorigenic inflammatory response. This review will discuss microRNAs as a key link between inflammation and cancer, and explain how studies of the latter can assist in the creation of innovative preventive and therapeutic approaches for cancer.
Eukaryotic Homologous Recombination Repair: A Dynamic Cast of Characters
Eric Greenwald, M.A. 2012
The repair of DNA double-strand breaks by homologous recombination is a high-fidelity pathway critical for preserving genomic integrity. Recombination depends on the concerted actions of many proteins, each of which is recruited to the site of the DNA break at a specific time point to catalyze a step of the overall process. Many of these repair factors in eukaryotes have been characterized through genetics, biochemical experiments with purified proteins, and the single-molecule imaging of interactions between proteins and individual DNA molecules. The findings of many of these investigations are reviewed here. Much attention has been paid to the timing of assembly of each of the role players during the recombination reaction. The implications of timescale data for the interdependencies of functionally related repair factors are also highlighted. Future objectives in the field of DNA damage repair are discussed at the conclusion.
Mitochondrial Diseases, Treatments, and FDA Orphan Legislation
Philip Hahn, M.A. 2012
Mitochondria originated during a key endosymbiotic event, when an enveloped bacterium or invasive parasite adjusted to its intracellular surroundings and formed the first eukaryotic cell. The symbiote evolved into a specialist organelle supplying the vast majority of a cell’s ATP energy supply as well as regulation of cellular differentiation, cell death, the cell cycle, and cell growth. Due to its double layered membranes and separate DNA control systems, it has proved an elusive target for medicines, and is responsible for a host of diseases and may be a key contributor to the aging process.
Mitochondrial disorders, though a diverse family ranging from cardiac diseases to a subset of Parkinson’s syndrome, individually affect relatively small populations and may therefore fall under the purview of the Orphan Drug legislation enforced by the Food and Drug Administration. While no viable delivery mechanism for macromolecules larger than proteins currently exists for the inner mitochondrial matrix, several academic research papers suggest that the unique morphological challenges of mitochondria may be overcome. A survey of these approaches is presented within the context of mitochondrial structure, and a path towards economical drug development via the Orphan Drug system is proposed.
Diminishing the Side Effects of Cancer Treatment by Improving Treatment Delivery
Alexander A. Kalin, M.A. 2012
Cancer is one of the leading causes of death in the world and is expected to become more prevalent each year. Cancer is caused by the uncontrollable growth of cells within the human body. This excessive growth can lead to the formation of malignant tumors, which invade parts of the body. Currently, the most common approach to treating cancer is surgery, chemotherapy, and radiation treatment. However, chemotherapy and radiation can cause drastic, harmful side effects to patients because they not only affect cancer cells, but normal proliferative cells as well. In many cases, a particular chemotherapy is avoided because the risks of side effects greatly outweigh the effect of the drug on the tumor. Therefore, if adverse effects are going to be eliminated and cancer treatment optimized, tumor cells must be specifically targeted and normal cells spared. One method of generating tumor specificity in cancer treatment that has recently gained interest and optimism is the use of medical devices. As technology has improved, the possibilities and applications of medical devices have become nearly limitless. In cancer treatment, medical devices can guide their cargo, whether it is a drug or radiation, directly to tumor sites within the patient. As a result, adverse effects should be diminished and cancer treatment should be optimized.
Wilms tumor X An X-linked tumor suppressor that acts through protein-protein interactions
Noopur V. Khobrekar, M.A. 2012
Wilms tumor X –WTX- is an X-linked tumor suppressor which is causal for Wilms tumors- pediatric nephroblastomas- through a single mutation event. WTX lacks conserved functional domains and acts solely through protein-protein interactions.
WTX interacts with diverse proteins in different cellular compartments. At the cell membrane, it functions as a negative regulator of the canonical Wnt signaling pathway by acting as a scaffold for the assembly of β-catenin destruction complex which constitutively degrades β-catenin. In the cytoplasm, it interacts with p53-MDM2 and CBP/p300 complexes to bring them in close proximity to activate p53 through acetylation. In the nucleus, it associates with another tumor suppressor WT1 to form an active transcription factor that transcribes several EGF-family genes including Vascular Endothelial Growth Factor – VEGF – which activates angiogenesis in hypoxic tissues. It also up regulates NRF-2 mediated antioxidant response during xenobiotic stress. Interestingly, WTX can directly bind viral oncoproteins and prevent them from binding and degrading tumor suppressor p53 in virus infected cells.
In this review, I present the classic signal transduction circuitry of the cell in light of tumor suppressor WTX as the central player that mediates crosstalk between different signaling pathways. I explore the complex molecular interactions between WTX and the key proteins in Wnt signaling pathway as well as the role of WTX in angiogenesis, anti-oxidant response and in counteracting viral oncoproteins. Finally, I propose a model where WTX emerges as a vital link between signaling through focal adhesion kinase at cellular adhesions and tumor suppressor p53 in the cytoplasm.
Diagnostic Tools and Treatments of Major Psychiatric Disorders
Caroline J. Kim, M.A. 2012
Psychiatric disorders like schizophrenia, major depressive disorder, and bipolar disorder can completely compromise patients’ quality of life. The need for a reliable psychiatric diagnostic tool had been apparent throughout the history. The DSM system has emerged as the standard diagnostic tool for mental disorders. Even though it has been praised for providing a practical way to categorize psychiatric disorders, DSM has also been criticized for its major limitations. Limitations include arbitrary categorization, high level of overlap among categories, and failure to define normality. In order to obtain more objective measures for psychiatric disorders, a lot of research focused on discovering the biological attributes of the diseases. Some of those identified attributes include shifted glucose metabolism, altered immune response, disturbed levels of neurotrophic factors, and abnormalities in oligodendroglia and myelination. Although premature, some of these discoveries are gradually being transitioned into the development of new psychiatric drugs with novel targets. Even so, medication treatments for schizophrenia, major depressive disorder, and bipolar disorder are largely limited to having a very small number of targets. Continued research efforts are required to further explore the measurable biological differences between psychiatric patients and healthy counterparts.
Stucture Biology of Membrane Proteins: Insights from Four Recent Examples
Jonathan Y. Kim, M.A. 2012
Membrane proteins play important roles not only a physiological level but in many fundamental biological processes. In fact, on a genome-wide scale, membrane proteins constitute approximately 20-30% of the proteins encoded by an organism. Despite their relevance as therapeutic targets for many human diseases, our knowledge of membrane protein structures is still scarce. Given the small number of membrane protein structures solved, we are still at an infant stage, especially compared to the wealth of information on soluble protein structures. This is mainly due to the amphiphilic nature of membrane proteins, which hampers the obtainment of well diffracting protein crystals. However, technological advancements and the development of novel methods have accelerated the progress of membrane protein structural determination. We expect to see a rapid growth in the number of membrane protein structures solved in the near future. Subsequently, the successful determination of membrane protein structures will uncover a plethora of insights into their physiological functions.
Perspectives on the applications of viral vectors in gene therapy
Katerina Leon, M.A. 2012
Since the beginning of gene therapy 50 years ago, research on potential gene replacement strategies has led to numerous promising but intangible results. The idea of gene therapy can be traced back to early transforming experiments on mammalian cells early in the 1960's. Then, with the advent of recombinant DNA technology during the 1970's, viral vectors were designed and developed as vehicles for efficient gene transfer. Ultimately, due to the viruses potential to integrate into the host genome and translate viral genes, three major kinds of viral vectors were eventually developed: retroviral vectors, adenoviral vectors, and adeno-associated viral vectors. These vectors have all been proven to be highly efficient at expressing foreign DNA in target cells. However, the widespread use of viral vectors have been severely limited by their associated toxicity and ability to elicit the host immune response, both of which counteracts their high transducing potential and raises strong concerns over their safety. As an alternative to viral vectors, the uses of non-viral based delivery systems have been explored (to a lesser extent). While non-viral delivery systems have the advantage of being safer, they also have the disadvantage of being less efficient at integrating foreign DNA into the host genome. To date, all the experiments and discoveries associated with gene therapy have only generated the approval and marketing of one gene therapy drug by the European Medicines Agency (EMA), which although considered a victory, may not be enough to revive the enthusiasm of the scientific community. On the other side, gene therapy to cure viral diseases like HIV is currently being explored. The use of viral vectors as vehicles to insert microRNAs, ribozymes, shRNAS and siRNAs to induce viral gene silencing has shown promising results. This thesis work will give an overview of gene therapy from its beginnings exploring the strategic manipulation of viruses and the role of gene therapy in fighting viral diseases.
Tissue Engineering of the Small Intestine
James L. Lynch, M.A. 2012
The principal aim of regenerative medicine, of which tissue engineering can be considered a specific subset, is to therapeutically regenerate or replicate functional tissues and organs to repair or replace diseased or damaged ones. Simple organs such as bladders and arteries have been successfully engineered. However, some organs, like the small intestine, are challenging to engineer successfully, due to their structural complexity. This review describes the basic framework for tissue engineering and its application to the structure of the small intestine, with a particular emphasis on the historical development and an evaluation of the current state of the art. Future applications are also discussed. Overall, significant advancements have been made in creating engineered small intestinal tissue. Current techniques are able to recreate the complex microstructures required for proper intestinal function; however further research is required to produce a fully functional small intestine due to its overall length and complex macrostructure.
Achieving Personalized Medicine through Pharmacogenetics: The Future of Healthcare
Jacqueline McCray, M.A. 2012
Pharmacogenetics comes at an important time, which, as the number of medications available to patients increases, there is continual removal of drugs from the market, due to harmful side effects. Here, the vast and rapidly growing field of pharmacogenetics is examined to highlight the need for personalized medicine, in order to minimize side effects that result as a consequence of genetic predisposition. In addition, I will propose how pharmacogenetics can become integrated into the healthcare field by overcoming several obstacles, while addressing several preconceived notions and addressing their validity. The future of healthcare could be improved by progress made in the field of pharmacogenetics.
The Role of Primary Cilia in Neuronal Development and Disease
Sara Nik, M.A. 2012
Primary cilia serve as an important sensory organelle found in eukaryotic cells. This organelle houses several multi-protein signaling complexes that carry out a wide array of functions that are important for normal development and cellular homeostasis. Additionally, it has been found that mutations in cilia-related genes result in developmental defects and a novel class of systemic disorders named ciliopathies. The hallmarks of ciliopathies are kidney cysts and mental retardation. While much progress has been made in elucidating the role of the primary cilia in the kidney, its function in brain development and cognitive disorders remain largely unknown. This holds particularly true for neuronal cells, which had long proven to be a difficult system for studying the role of primary cilia, until 13 years ago upon the discovery of markers that selectively labeled neuronal cilia. This review will focus on the field of study regarding the role of the primary cilium in mammalian neuronal development and disease, and the key advances that have helped further this field.
Hereditary Non-Polyposis Colon Cancer: Important Molecular Causes and Therapies
Akanksha Nayak, M.A. 2012
Hereditary non-polyposis colon cancer is one of the types of inherited colon cancers. It occurs as a result of germline mutations in certain genes, primarily those involved in the mismatch repair pathway. Most of the molecular and genetic causes underlying hereditary non-polyposis colon cancers have been identified. As a result of the defects in the mismatch repair genes, repetitive sequences in other genes are also affected. These molecular features that define hereditary non-polyposis colon cancer are reviewed here along with some of the screening techniques and treatment possibilities for this disorder. Current therapeutic techniques are limited to surgery or approaches traditionally used to treat most cancers. Certain novel approaches that target the direct cause must be studied further.
Searching for Rare Mutations in Patients with Congenital Anomalies of the Kidney and Urinary Tract
Brittany J. Perry, M.A. 2012
Congenital anomalies of the kidney and urinary tract, also known as CAKUT, are of high prevalence in newborns and in adults. Early diagnosis of these defects may allow for the best medical or surgical treatment in attempt to prevent or decelerate the development of chronic kidney disease. Understanding the underlying genetics of these anomalies could greatly improve efforts of gene therapies leading to decline of incidence of chronic kidney disease. In effort to detect genetic mutations in the genome, we implemented an innovative approach using linkage analysis and whole exome sequencing. Linkage analysis was performed for seventeen family members of a family with many affected members. Two of these family members were also subjected to whole exome sequencing. The linkage analysis revealed ten peaks across the genome. The exome sequencing results were analyzed against this data and lead to one pathogenic splice site mutation identified in a gene under one of the linkage peaks. Sporadic patients were then screened for mutations in this gene to reveal an additional three missense mutations, an early stop codon, and a putative splice site mutation. These results clearly supported the identification of a novel gene that predisposes to CAKUT and demonstrated the successful implementation of linkage analysis coupled with exome sequencing to determine novel pathogenic genes for human diseases.
Molecular Signatures in Breast Cancer: Past, Present and Future
Aidan S. Quinn, M.A. 2012
The molecular biology epoch has been driven largely by the development of several biotechnologies that have profoundly expanded the amount of biological data available including next generation sequencing and microarray platforms. Specifically, these technologies allow researchers to interrogate gene expression extremely efficiently and in a massively parallel fashion, thus yielding copious amounts of expression data. Molecular profiling analyses were developed in response to the challenge of analyzing this valuable data. This review discusses several major techniques that have been used to generate molecular profiles for breast cancer, the application of existing molecular signatures to both research and clinical medicine, and the future directions that will lead to more robust molecular signatures. Overall, molecular profiles represent an extremely useful tool for understanding basic biology and clinical pathology that despite some limitations, have yielded some very important findings and advanced out knowledge of breast cancer and biology in general.
Current Ex-vivo Gene Therapy Technology and Future Developments
Ziwei Song, M.A. 2012
With the increasing prevalence of diabetes, extensive efforts have been made to find effective approaches for diagnosis as well as treatment. Approximately 90 to 95 percent of those affected adults have type II diabetes mellitus (T2DM). T2DM is a complex metabolic disorder characterized by defects in insulin secretion and insulin action. This literature review covers treatment modalities for T2DM, emphasizing on gene therapy. Conventional treatments are lifestyle modification, oral medication, and insulin therapy. To increase the treatment efficiency and reduce the side effects, various modalities have been made. Also with the completion of human genome project and the launch of personal genome project, gene therapy has been proposed as a more effective and targeted therapy. The fundamental issue is to reveal genes and pathways involved in T2DM development. Main approaches to identify the defective genes include linkage analysis, candidate-gene association studies, and whole genome association studies. A large number of genes have been identified and can be roughly categorized to be involved in insulin resistance, insulin secretion and obesity. For future research, the disease pathogenesis and its underlying molecular etiology of T2DM need to be verified before the launch of its gene therapy, and the interaction of genetic factors and environmental factors should be fully understood.
Behind the switchboard: the role of Rho GTPase control of cellular processes and cancer progression
Lauren C. Strazzulla, M.A. 2012
The role of Rho GTPases in cellular processes cannot be underestimated as they control a myriad of processes including actin cytoskeleton organization, epithelial architecture, endothelial integrity and even the cell cycle. Yet, these small GTPases have also been implicated in promoting cancer by inducing a more motile phenotype as well as initiating extravasation through increased endothelial permeability. Through animal models and the use of bacterial toxins, much insight has been gained into the complex pathways through which Rho GTPases function. As a result there have been calls to develop therapies that target Rho expression levels. Though this drug development strategy has not yet produced a viable result yet, the groundwork has been laid for refining Rho expression levels to combat malignancy.
Current Ex-vivo Gene Therapy Technology and Future Developments
Chen-Hsien Su, M.A. 2012
Ex-vivo gene therapy falls into two categories, traditional gene additional therapy and gene correction therapy. Gene additional therapy inserts the therapeutic gene to treat the disease caused by the abnormal gene function in the genome while the abnormal gene remains intact. Gene correction therapy, instead of creating the coexisting of both abnormal gene and the therapeutic gene, it directly replaces the abnormal gene with the therapeutic gene. In gene correction therapy, homologous recombination technology is applied to replace the abnormal gene with the therapeutic gene. Nonetheless, it is refrained by the low efficiency of accurate recombination event. Recently, engineered zinc finger nucleases (ZFNs) were found to successfully stimulate homologous recombination by inducing double-strand break at specific DNA site. Another enzyme, transcription activator-like effector nucleases (TALENs) were also found to be capable of inducing specific DNA double-strand breaks and could be a potential gene manipulation tool as well.
Gene correction on the stem cells and induced pluripotent stem cells made gene therapy more feasible in practical. Cells from the patients are harvest and go through proper induction process to reprogram into high pluripotency cells as stem cells. These cells have the potential of differentiating into variety of cells. Gene correction therapy could be applied on these cells, with proper induction to make them differentiate into desired mature cells to reimplant back into the patients to treat the disease. To date, the efficiency of gene targeting is still low. With further research on the stem cells and induced pluripotent stem cells, gene therapy on the stem cells would be the most potential treatment to the genetic diseases in the future.
Tissue Engineering of Skin: Scope and Future
Mansi Vasistha, M.A. 2012
The purpose of this study was to review the field of tissue engineering of skin for its use, scope and future. Tissue engineered skin has a widespread application to produce functional replacement of skin or soft tissue in clinical applications. One of the function of a tissue-engineered skin is to provide a barrier layer of renewable keratinocytes (the cells that form the upper barrier layer of our skin), which is securely attached to the underlying dermis, well vascularized, and provides an elastic structural support for skin.
Skin injuries in which the upper epidermal layer is completely lost but part of the dermis remains, the epidermal keratinocytes (most common cell type of epidermis) lining the dermis (in the areas in dermis such as sweat glands and hair follicles) will rapidly migrate out of the dermis and form a new epithelium. However, if the epidermis and all of the dermis is lost, then this represents a major problem. There are two options in such a scenario - if the injury is not too extensive, then surgeons will take a split-thickness skin graft (all of the upper epidermal layer of skin and some of the underlying dermal layer) from elsewhere in the body and use it to graft the damaged area. The site from which the skin graft has been removed will then heal by keratinocytes within the dermis migrating upwards and proliferating. But if the injury is extensive then tissue engineering of skin provides reliable alternatives to cope with it. In addition to burns injuries, tissue-engineered materials can also benefit patients with chronic ulcers and those requiring reconstructive surgery.
Distinct Synthetic Lethal Interactions in Various Mutated Tumors
Nengyi Zhou, M.A. 2012
Cancer treatment remains a challenge during the last several decades. With identification of many mutations of tumor suppressor genes and oncogenes, targeted therapies against these mutations are available for some cancers and demonstrate some effectiveness for limited cancers, but most of these targeted therapies such as those for KRAS-mutated cancers could not reach optimal efficacy with low toxicity. Identification of synthetic lethal interactions may provide optimal targets suitable for targeted therapies that are specific for cancer cells, with the minimal interruption on normal cells. Chemical high-throughput screen is able to identify synthetic lethal compounds, which need further clarification of protein targets of these compounds. RNAi-based genetic screen is a powerful strategy to identify the synthetic lethal genes, which provides the protein targets for drug development. Several synthetic lethal interactions have been identified in BRCA1/2-, PTEN-, and especially KRAS-mutated cancers. In KRAS-mutated cancers, mitotic machinery components, such as PLK1, APC/C, CDK1, and Survivin, proteasome, and STK33 showed synthetic lethality. Mitotic vulnerability is the characteristics of the KRAS-mutated cancers, which may be caused by KRAS-induced strong S-phase signaling stress that suppresses the mitotic machinery. In BRCA1/2-mutated breast or ovarian cancers, there is a DNA repair deficiency and PARP showed synthetic lethality which is essential for DNA repair in BRCA1/2-mutated cancers. These synthetic lethal genes are generally non-oncogenic without mutation in cancers, but essential for cancer cell survival after specific gene mutation, supporting the non-oncogene addiction theory. Manipulations of these synthetic lethal interactions have showed significant effectiveness in the treatment of these mutant cancers. PLK1 inhibitor can promote the therapy efficacy of paclitaxel in the treatment of KRAS-mutated solid tumors and myeloma. PARP inhibitor demonstrates good effects in the treatment of BRCA1/2-mutated breast and ovarian cancers. Identification and targeting of synthetic lethal interactions will be promising to make a breakthrough in the treatment of cancers without high toxicity. Identification of synthetic lethal interactors for other commonly mutated genes such as RB1, PTEN, EGFR, etc. is necessary for cancer treatment, but remains a challenge in the field. Creation of isogenic control cell line is one of the obstacle needs to be solved for screen. A close collaboration among cancer biologists, structure biologists, chemists, and pharmacologists is necessary for the transition from identification of lethal genes to drug development.