Our research group utilizes the nematode C. elegans to investigate germ cell immortality: mechanisms that allow germ cells remain eternally youthful as they are transmitted from one generation to the next. We also study how telomerase functions at chromosome termini, as well as the consequences of telomere dysfunction.
Research is aimed at evaluating genetic and epigenetic mechanisms in environmental chemical carcinogenesis. Specific project areas are concerned with toxicity assessments of conazole pesticides, arsenic, and water
disinfection by-products. Human and rodent cells are analyzed for chemical-induced alterations in DNA
methylation and gene expression in combination with chromosome damage, cell toxicity and histopathological
effects. Ultimate goals are to improve the scientific basis of risk assessment, and include evaluations of lifestage
and nutritional susceptibility risk factors which may modulate chemical toxic/carcinogenic effects.
Our laboratory studies an amazing regulatory factor known as NF-kappaB. This transcription factor controls key developmental and immunological functions and its dysregulation lies at the heart of virtually all major human diseases.
We study the interface between signal transduction and cell function. Approaches employed include - molecular genetics, protein and lipid biochemistry, confocal and electron microscopy, protein crystallography, and model organisms approaches (e.g. yeast, Arabidopsis, C. elegans, mouse gene knockout technology).
Blood vessel formation in cancer and development; use mouse culture (stem cell derived vessels) and in vivo models (embryos and tumors); genetic, cell and molecular biological tools; how do vessels assemble and pattern?, dynamic image analysis.
The goal of our laboratory is to investigate mechanisms of tumorigenesis and tumor progression, and to apply genome-wide techniques to develop anti-cancer therapies. Our research focuses on transcriptional regulation of gene expression during stem cell self-renewal and differentiation and during tumorigenesis. We use artificial transcription factors (ATFs) as genetic probes to identify genes and gene pathways responsible for the appearance of specific malignant phenotypes and we investigate the ability of these ATFs to interfere with tumor cell regulatory programs. Cancer cell reprogramming with such artificial genetic switches may afford a new therapeutic strategy.
We are interested in the mechanism by which eukaryotic cells are polarized and the role of vesicle transport plays in the determination and regulation of cell polarity and tumorigenesis.
Our lab is interested in the role of chromatin-modifying factors and epigenetics in mammalian development and disease. We are particularly interested in two major areas both of which make use of mouse models: (1) the role of BRG1 and SWI/SNF nucleosome-remodeling complexes in various aspects of hematopoiesis including regulation of globin gene expression and inflammation; (2) the role of dietary fiber and gut microflora on histone modifications, CpG methylation, and prevention of colorectal cancer.
Cell adhesion, both to other cells and to ECM, signaling, the cytoskeleton and cell migration. The Rho family of GTPases, their regulation by guanine nucleotide exchange factors and GAPs. Inflammation and leukocyte transendothelial migration.
The Cancer Biology Group at NIEHS focuses on early events in skin tumor development using a transgenic mouse model (TgAC). This model possesses a v-Ha-ras transgene under the regulation of a fetal globin promotor integrated at an ectopic site which confers a unique phenotype of inducible skin papillomas with a high rate of progression to invasive squamous and spindle cell neoplasms. The goals of our studies are to identify and characterize: 1) The cellular origin of the tumors and 2) critical genes which are involved in ras-mediated tumor induction and progression. Conventional cancer therapies have until recently depended on treatment late stages of tumor growth and involved non-specific mechanisms of cellular injury. By focusing on understanding early events in tumor induction we hope to gain insights into targets for intervention that can more specifically inhibit cancer cell growth.
Developing and applying novel mass spectrometry (MS)-based proteomics methodologies for high throughput identification, quantification, and characterization of the pathologically relevant changes in protein expression, post-translational modifications (PTMs), and protein-protein interactions. Focuses in the lab include: 1) technology development for comprehensive and quantitative proteomic analysis, 2) investigation of systems regulation in toll-like receptor-mediated pathogenesis and 3) proteomic-based mechanistic investigation of stress-induced cellular responses/effects in cancer pathogenesis.
Our research centers on the cell biology and biochemistry of motor proteins and the cytoskeleton and their roles in processes such as cell crawling, phagocytosis, organelle transport.
Our research is concerned with proteases and their inhibitors in various disease processes (thrombosis and cancer); our science tools are structure-activity, cell biology and signaling, pathobiology, immunohistochemistry, and in vivo models.
Steroid hormones regulate tissue-specific gene expression in animals via receptor dependent intracellular signal transduction pathways. We are particularly interested in glucocorticoid receptors and their actions on the immune system because they reflect the primary response to environmental stress. Current research projects are examining the following aspects of glucocorticoid hormone action. A second major interest of the laboratory focuses on evaluating the mechanisms involved in the regulation of apoptosis in normal and neoplastic cells. Research is aimed at the identification and cloning of genes that are responsible for both the initiation and execution of apoptosis.
The research in our laboratory involves several major projects related to the molecular pathogenesis of human cancer and investigations related to the biology of liver stem-like progenitor cells, including (i) characterization of human liver tumor suppressor genes, (ii) analysis of genetic determinants of breast cancer, (iii) investigation of mechanisms governing aberrant DNA methylation in breast cancer, (iv) liver progenitor cell responses after toxic liver injury, and (v) transplantation of liver stem-like progenitor cells for correction of genetic liver disease.
We study cell cycle control of DNA replication licensing, the process that renders replication origins competent to initiate DNA synthesis. We investigate how the replication process is linked to cell cycle progression and the signaling pathways that gather and transmit information about the cellular environment. Our experimental approach is to manipulate human cells in culture (both cancer cell lines and normal cells) through a variety of molecular and genetic strategies; some projects utilize budding yeast as a model system due to the sophisticated genetic tools available in that organism. We measure protein abundance and stability, chromatin localization and modifications, cell cycle progression, protein-protein interactions, and checkpoint functions. Our long-term goals are to understand the molecular events that ensure genome stability and how those events are disrupted in cancer cells.
The primary research area my lab is the regulation of meiotic recombination at the genomic level in higher eukaryotes. Genomic instability and disease states, including cancer, can occur if the cell fails to properly regulate recombination. We have created novel tools that give our lab an unparalleled ability to find mutants in genes that control recombination. We use a combination of genetics, bioinformatics, computational biology, cell biology and genomics in our investigations. A second research area in the lab is the role of centromere DNA in chromosome biology. We welcome undergraduates, graduate students, postdoctoral fellows and visiting scientists to join our team.
Mechanisms of DNA replication, DNA repair, and cell cycle checkpoints are studied in cultured human cells and using biochemical assays in vitro. It includes translesion synthesis by DNA polymerase eta and its role in suppressing mutagenesis by solar radiation. Inherited and acquired defects in the network of protection of genetic stability are associated with increased risk for mutations underlying cancer pathogenesis. Current goals are to identify key molecular events in melanoma development associated with sun exposure. Other collaborative studies aim at localization of functional origins and characterization of DNA replication dynamics.
Our lab is interested in molecular mechanisms of oncogenesis, specifically as regulated by Ras and Rho family small GTPases. We are particularly interested in understanding how membrane targeting sequences of these proteins mediate both their subcellular localization and their interactions with regulators and effectors. Both Ras and Rho proteins are targeted to membranes by characteristic combinations of basic residues and lipids that may include the fatty acid palmitate as well as farnesyl and geranylgeranyl isoprenoids. The latter are targets for anticancer drugs; we are also investigating their unexpectedly complex mechanism of action. Finally, we are also studying how these small GTPases mediate cellular responses to ionizing radiation - how do cells choose whether to arrest, die or proliferate?
The work in our laboratory is focused on understanding the molecular pathogenesis of Kaposis sarcoma-associated herpesvirus (KSHV), an oncogenic human virus. KSHV is associated with several types of cancer in the human population. We study the effect of KSHV viral proteins on cell proliferation, transformation, apoptosis, angiogenesis and cell signal transduction pathways. We also study viral transcription factors, viral replication, and the interactions of KSHV with the human innate immune system. Additionally, we are developing drug therapies that curb viral replication and target tumor cells.
With a particular interest in pediatric solid tumors, our lab aims to develop a mechanistic understanding of the role of aberrant or dysregulated transcription factors in oncogenesis.
Our research centers on understanding the
molecular basis of human carcinogenesis. In particular, a major focus of our studies is the Ras oncogene and Ras-mediated signal transduction. The goals of our studies include the delineation of the complex components of Ras signaling and the development of anti-Ras inhibitors for cancer treatment. Another major focus of our studies involves our validation of the involvement of Ras-related small GTPases (e.g., Ral, Rho) in cancer. We utilize a broad spectrum of technical approaches that include cell culture and mouse models, C. elegans, protein crystallography, microarray gene expression or proteomics analyses, and clinical trial analyses.
We study how mammalian cells activate the programmed cell death pathway and die by apoptosis. We have focused our work on identifying unique mechanisms by which this pathway is regulated in postmitotic cells such as neurons, cardiomyocytes, and myotubes, as well as cancer, senescent, and stem cells. Excessive cell death is seen in many pathological conditions such as after stroke, neurodegeneration or cardiovascular diseases. In contrast, reduced cell death is a hallmark of cancers. Therefore, discovering the mechanism by which mammalian cells regulate cell death has significant therapeutic implications.
The direct fabrication and harvesting of monodisperse, shape-specific nano-biomaterials are presently being designed to reach new understandings and therapies in cancer prevention, diagnosis and treatment.
Our lab tries to understand viral pathogenesis. To do so, we work with two very different viruses - West Nile Virus (WNV) and Kaposis sarcoma-associated herpesvirus (KSHV/HHV-8).
Mechanisms of cell cycle control by cyclin dependent kinases (CDK's) and gene expression during Drosophila development, including how transcription factors (the pRB tumor suppressor and E2F), RNA metabolism (histone pre-mRNA processing), and protein ubiquitination and proteolysis (cullin dependent ubiquitin ligases) regulate the G1-S transition and DNA replication.
Our lab is interested in how signals from membrane receptors are transduced to the nucleus altering gene expression, cell shape, proliferation and differentiation. We are particularly interested in tyrosine-specific protein kinases in breast and prostate cancer, as well as lymphoma/leukemia. Particular focus of the lab include:1) roles of the EGF receptor family and related molecules HER4/ErbB4 in growth inhibition and differentiation and 2) Mer (a novel receptor tyrosine kinase) and how signals downstream from Mer enhance prostate tumorigenesis.
Genetic instability in cultured human cells and yeast, microsatellite mutations, DNA mismatch repair, hereditary nonpolyposis colorectal cancer (HNPCC, Lynch syndrome), human genetics, somatic-cell genetics.
The central goal of my research is to understand how immune cells are activated and regulated within the Central Nervous System. Our research looks at the different pathways of activation of the microglia, the role of the microglia in sensory responses, and the role of stress responses in activating and regulating the response of the microglia. We are currently investigating the mechanism of microglia activation and regulation in Parkinson's Disease (PD). We also study the mechanisms by which CD8 T lymphocytes dictate the nature of inflammatory responses to cancer cells. Research in my laboratory seeks to delineate the immunologic mechanisms involved in the generation of protective anti-tumor responses in CD8 cell populations, and in developing therapies for treatment of cancer.
We are using C. elegans embryos to address fundamental issues such as how cells move to specific positions during embryonic morphogenesis, how the orientation of cell division is determined, how the mitotic spindle is positioned in cells and how cells respond to cell signaling. We use diverse methods, including methods of cell biology, developmental biology, forward and reverse genetics including RNA interference, biochemistry, molecular biology and live microscopy of cells and the cytoskeleton. We are also developing water bears as a
new model system to study the evolution of development.
Our primary research is in the area of computational systems biology, with particular interest in the study of biological signaling networks; trying to understand their structure, evolution and dynamics. In collaboration with wet lab experimentalists, we develop and apply computational models, including probabilistic graphical and multivariate methods along with more traditional engineering approaches such as system identification and control theory, to current challenges in molecular biology and medicine. Examples of recent research projects include: prediction of protein interaction networks, multivariate modeling of signal transduction networks, and development of methods for integrating large-scale genomic data sets.
My lab studies a gene silencing phenomenon called RNA interference, or RNAi. We are interested in the role of RNAi in regulating endogenous genes, particularly those involved in cancer progression pathways.
This laboratory focuses on the identification of signaling pathways regulating host/bacteria interaction and the pathological consequences of a dysregulated response. Using germ free mice and gnotobiotic approaches, we investigate the functional impact of toll-like receptor (TLR) and nucleotide oligomerization domain (Nod) signaling on bacteria-mediated intestinal inflammation, colitis-associated colon cancer and intestinal response to injury (ischemia-reperfusion, radiation).
Spatio-temporal regulation of signal relay systems in cells using live cell fluorescence imaging and targeted gene disruption of signaling proteins to define their role in development, physiology and pathophysiology.
Research interests include: 1) Regulation of signal transduction and cell growth by integrin-mediated cell adhesion and 2) Therapeutic drug design and delivery.
Topic 1 We seek genomic targets for carcinogenesis among segments of DNA replicated in early S phase when cells are most susceptible to carcinogens. We are mapping genomic sites replicated during early S phase, identifying origins of replication activated in this interval, and characterizing temporal sequencing of replication from these origins. Topic 2 We are reconstructing differentiated and functional human endometrial tissue from epithelial and stromal cells interacting in culture. We use these co-cultures to study development of endometrial cancer.
Research in the Kaufmann laboratory is concerned with determining the mechanisms whereby cell cycle checkpoints suppress human cancer development. We are focused on two checkpoints that help to stabilize the genome. The decatenation G2 checkpoint delays mitosis until daughter chromatids are sufficiently disentangled by topoisomerase II. This checkpoint is regulated by the breast cancer susceptibility gene BRCA1. The intra-S checkpoint regulates DNA synthesis by controlling the rates of replicon initiation and DNA chain elongation. This checkpoint is regulated by two proteins, Timeless and Tipin, that mediate signaling at stalled replication forks. A program project is studying how the Timeless-Tipin replication fork protection complex protects against UV-induced chromosomal damage and sunlight-induced melanoma.
Our research explores the role of hypoxia-inducible factor (HIF) in tumorigenesis. HIF is a transcription factor that plays a key role in oxygen sensing, the adaptation to hypoxia and the tumor microenvironment. It is expressed in the majority of solid tumors and correlates with poor clinical outcome. Therefore, HIF is a likely promoter of solid tumor growth and angiogenesis. Our lab uses mouse models to ask if and how HIF cooperates with other oncogenic events in cancer. We are currently investigating HIF’s role in the upregulation of circulating tumor cells and circulating endothelial cells.
We use high-throughput DNA sequencing, microarrays, and other technologies to study how and where proteins interact with the genome, and how these interactions affect the biology of living cells. We use three systems: yeast, C. elegans and human. Our C. elegans studies focus on developmental processes, and we use human cell lines and clinical samples to study diseases like cancer and diabetes. All of our projects focus on chromatin and DNA-binding proteins.
Molecular, cellular and in vivo approaches in intestine to define mechanisms by which hormones and growth factors regulate normal growth and cancer. Uses model cell lines, mutant mice, mouse models of disease, translational approaches to growth factor action and signal transduction, gut immune interactions in obesity.
The Magnuson Lab works in three areas - (i) Novel approaches to allelic series of genomic modifications in mammals, (ii)Mammalian polycomb-group complexes and development, (iii) Mammalian Swi/Snf chromatin remodeling complexes
We are interested in the mechanisms by which histone protein synthesis is coupled to DNA replication, both in mammalian cell cycle and during early embryogenesis in Drosophila, Xenopus and sea urchins.
Research in our laboratory is focused on the enzymatic mechanisms and biological roles of DNA helicases. These enzymes provide the primary mechanism by which duplex DNA is converted to single-stranded DNA (ssDNA) for use as a template in DNA replication and repair or as a substrate in recombination. Indeed, these enzymes are essential for DNA replication, repair and to maintain genomic stability in all organisms. Consistent with this idea, defects in genes encoding DNA helicases in human cells have been linked to genomic instability leading to a variety of progeriod disorders and human cancers. The bacterium E. coli and the budding yeast S. cerevisiae provide attractive systems in which to pursue these studies due to the ease of genetic manipulation and the ability to isolate enzymes for biochemical studies. The long-range goal of the research program is to understand, in enzymatic and molecular terms, the mechanism of action of several helicase enzymes, and to define their individual roles in DNA metabolism.
The lab also has an interest in the process of DNA transfer by bacterial conjugation, first observed more than 50 years ago as the unidirectional and horizontal transmission of genetic information from one E. coli cell to another. Today we know that conjugative DNA transfer plays a role in increasing genetic diversity in addition to propagating the spread of antibiotic resistance and microbial virulence factors. Recent work in this laboratory and others has provided a working model of DNA transfer in the F plasmid system. The long-range goal of this research program is to define the function and regulation of the relaxosome, and each protein in this nucleoprotein complex, in conjugative DNA transfer. Based on that information we will begin to establish inhibitors of relaxosome function.
Our laboratory is interested primarily in the responses of macrophages during injury to the central nervous system and during inflammation after insult by bacterial pathogens. We use molecular, cellular and biochemical approaches both in vitro and in vivo to identify the function of key mediators during pathogenesis.
My laboratory studies diffuse gliomas, devastating primary tumors of the central nervous system for which few effective drugs are currently available. We utilize model systems (genetically engineered mice, cultured cells, and human tumor specimens) to explore the molecular pathogenesis of
and develop drugs and diagnostic markers for individualized therapy of gliomas. Rotating students gain experience with techniques that include genomics (expression microarrays and array CGH), fluorescence microscopy, computer-enhanced image analysis, and tissue microarrays.
Dr. Millikan's research interests include the role of genetics in human cancer, including the study of how inherited variation in DNA repair interacts with environmental factors in breast cancer, colon cancer, and malignant melanoma. He is also interested in carcinogen metabolism, and identifying causes of breast cancer in young women and African American women.
Mechanisms by which cells control their shape via modulation of the actin cytoskeleton. Palladin, a novel cytoskeletal protein, may be involved in organizing the actin cytoskeleton as a scaffolding protein and may contribute to changes in cell shape.
Cell adhesion, signal transduction, and cytoskeletal regulation during embryogenesis and in cancer. We focus on the regulation of cadherin-based cell-cell adhesion, and on Wnt signaling and its regulation by the tumor suppressor APC.
Human carcinomas show great diversity in their morphologies, clinical histories and in their responsiveness to therapy. This wide tumor diversity poses the main challenge to the effective treatment of cancer patients. The main focus of the Perou Lab is to characterize the biology diversity of human tumors using microarray analysis, genomics, molecular genetics, and cell biology, and then to mimic these findings in animal models. We ultimately use these animal systems to develop predictive computational models and to test new therapeutics that are specific for each tumor subtype.
My graduate students and I use the formalism of equilibrium thermodynamics and the tools of molecular biology and biophysics to understand how nature designs proteins.
Our laboratory investigates the role of the Epstein-Barr virus in the etiology of human disease. EBV is a ubiquitous infectious agent, which is associated with specific malignancies including Burkitt's lymphoma, Hodgkin's lymphoma, and nasopharyngeal carcinoma (NPC), which develop with high incidence in endemic areas. EBV is etiologic for post-transplant lymphoma and also causes the AIDS-associated disease, hairy leukoplakia (HLP). We have identified three viral genes, which are consistently expressed and have identified a new family of transcripts that are expressed at particularly high levels in NPC tissue. These new mRNAs are intricately spliced and contain several new open reading frames which could potentially code for protein. We have shown one of these open reading frames does encode a protein that is expressed at high levels in EBV associated cancers. Current studies are investigating the potential functions of this gene using the two hybrid analysis in yeast cells and by determining its intracellular location with confocal microscopy.
The end joining pathway is a major means for repairing chromosome breaks in vertebrates. My lab is using cellular and cell-free models to learn how end joining works, and what happens when it doesnt.
Identification of airway epithelial stem cells; innate immunity in the airway; the pathophysiology of post-lung transplant ischemia reperfusion injury and bronchiolitis obliterans syndrome.
The focus of my research group is the tumorigenesis of renal cell carcinoma. Our approach utilizes genetically engineered cells expressing clinically important point mutations in genes identified from renal cancers. Using cellular and animal models we are able to investigate processes integral to tumorigenesis including angiogenesis, hypoxic response signaling, extracellular matrix remodeling, and cell cycle signaling. Using data from the experimental models, I oversee a clinical research program that offers biologically active protocols to patients with renal cell carcinoma and examines correlative radiographic and serum or tumor biomarkers of tumor response to treatment.
Two dynamically interacting sets of mechanisms govern tissue-specific gene expression and cell growth. 1) mechanisms in lineage biology regulate stem cells and their descendents, processes that define the repertoire of genes available to be regulated and 2) signal transduction mechanisms, induced by the synergistic effects of extracellular matrix components and soluble signals (hormones, growth factors), regulate the expression of the available genes. Studies in the lab focus on both classes of mechanisms in normal versus neoplastic tissue.
The Chromosomal Stability Group integrates mechanisms and genetic controls of genome stability with environmental factors and stress responses to better understand their complex contributions to human health. Using budding yeast and human cell models, research focuses on genome maintenance and natural or environmental challenges to chromosome stability. Repair, replication and checkpoint functions are investigated to understand sources of genome instability and mechanisms of coping with DNA damage, particularly double-strand breaks. Included in these studies are the roles that human genes and networks, particularly p53, play in stress responses.
The research in our lab is centered on understanding the mechanisms and principles of movement at the cellular level. Cytoskeletal filaments - composed of actin and microtubules - serve as a structural scaffolding that gives cells the ability to divide, crawl, and change their shape. Our lab uses a combination of cell biological, biochemical, functional genomic, and high resolution imaging techniques to study cytoskeletal dynamics and how they contribute to cellular motion.
Bioinformatics, Cancer Biology, Cell Biology, Chemical Biology, Computational Biology, Genomics, Molecular Medicine, Neurobiology, Pharmacology, Systems Biology, Toxicology, Translational Medicine
We are engaged in studying the molecular biology of the human parvovirus adeno-associated virus (AAV) with the intent to using this virus for developing a novel, safe, and efficient delivery system for human gene therapy.
We have three main areas of research focus: (1) Nucleotide excision repair: The only known mechanism for the removal of bulky DNA adducts in humans. (2) DNA damage checkpoints: Biochemical pathways that transiently block cell cycle progression while DNA contains damage. (3) Circadian rhythm: The oscillations in biochemical, physiological and behavioral processes that occur with the periodicity of about 24 hours.
Cell adhesion controls cellular functions implicated in human disease, e.g. cancer. FAK, a tyrosine kinase, is a major component of this signaling pathway. We study the function and molecular mechanisms by which FAK controls these events.
Genome instability is a major cause of cancer. We use the model organism Drosophila melanogaster to study maintenance of genome stability, including DNA double-strand break repair,
meiotic and mitotic recombination, and characterization of fragile sites in the genome. Our primary approaches are genetic (forward and reverse, transmission and molecular), but we are also using biochemistry to study protein complexes of interest, genomics to identify fragile sites and understand the regulation of meiotic recombination, fluorescence and electron microscopy for analysis of mutant phenotypes, and cell culture for experiments using RNA interference.
Our laboratory is involved in studies to determine the mechanisms and proteins involved in the migration of alloreactive and regulatory T cells to organs involved in graft-versus-host disease after stem cell transplantation using mouse models.
The lab relies on murine genetic approaches to study the roles of the INK4/ARF tumor suppressor locus in human cancer and aging. At present, the lab has two main focuses:
Stem Cell Aging:
Cancer and degenerative diseases are much more common in old people than young. Although this has been well-recognized in clinical medicine for decades, scientists do not agree as to why this occurs. Recently, work from several labs including our own has shown that humans age, in part, because important regenerative cells lose their capacity to divide with the passage of time. That is, the tissues and organs from old people are less able to replace and regenerate lost or damaged cells than the corresponding tissues and organs from young people. Our lab has studied mechanisms that underlie this age-dependent failure of cell division; in fact, we have shown the surprising result that cellular programs that function to prevent cancer untowardly also calls aging. Specifically, cellular “senescence” is now believed to be of major importance in the process of aging. Senescence refers to a permanent growth arrest induced in formerly dividing cells by the activation of genes that prevent cancer. The good news in this system is that the normal functioning of these ‘tumor suppressor genes’ prevents cancer; the bad news is that these same genetic events appear to cause aging by activating cellular senescence.
Melanoma and Murine Models of Cancer:
Because of the important role of p16INK4a in preventing melanoma, the lab has long been interested in this particularly deadly form of skin cancer. Specifically, we are interested in using genetically engineered models of cancer to study melanoma genetics. We have shown a role for the p16INK4a-RB and ARF-p53 tumor suppressor pathways in repressing this important human cancer in response to RAS-RAF activation. We have generated highly faithful models of human melanoma, and have used these to study novel therapeutics. We have also discovered a novel human melanoma sub-type based on expression profiling, and have identified a new therapeutic target (CD200) for treatment of melanoma.
Regulator of G-protein signaling (RGS) proteins accelerate the GTPase activity of G-alpha subunits and thereby act as critical negative regulators of hormone and neurotransmitter signaling via G protein-coupled receptors. Our lab first recognized the existence of these critical signaling regulators in 1996. We continue to study their structural and functional diversity, as well as their roles in physiological and disease processes, including immunity, oncogenic transformation, and pain processing.
Our lab examines cytoskeletal dynamics, the molecules that regulate it and the biological processes it is involved in using live cell imaging, in vitro reconstitution and x-ray crystallography. Of particular interest are the microtubule +TIP proteins that dynamically localize to microtubule plus ends, communicate with the actin network, regulate microtubule dynamics, capture kinetochores and engage the cell cortex under polarity-based cues.
Our laboratory studies signal transduction systems controlled by heterotrimeric G proteins as well as Ras-related GTPases using a variety of biophysical, biochemical and cellular techniques. Member of the Molecular & Cellular Biophysics Training Program.
Our laboratory is examining the role of histone post-translational modifications in chromatin structure and function. Using a combination of molecular biology, genetics and biochemistry, we are determining how a number of modifications to the histone tails (e.g. acetylation, phosphorylation, methylation and ubiquitylation) contribute to the control of gene transcription, DNA repair and replication.
My laboratory studies development and function of the human immune system and human liver, and HIV-1/HCV infection and immuno-pathogenesis. 1. Humanized mouse models to study human hamatopoietic stem cells (HSC), thymus and liver stem cells. 2. FoxP3 and regulatory T (Treg) cells in viral infection and immuno-pathogenesis. 3. Modeling immuno-pathogenesis and immuno-therapy of chronic HIV and HCV.
My laboratory focuses on understanding mechanisms of carcinogenesis, with emphasis on the role of DNA damage and repair. During the last few years, we have developed ultra-sensitive and highly specific mass spectrometry methods for measuring the DNA and hemoglobin adducts of vinyl chloride, crotonaldehyde, ethylene oxide, propylene oxide, styrene oxide, butadiene, malondialdehyde, cis-platin and O6-methyldeoxy-guanosine, as well as slotblot methods for AP sites and oxidative DNA damage. These methods have been applied to understanding critical mechanisms in carcinogenesis, as well as undertaking molecular epidemiology studies of workers in the butadiene and reinforced plastics industries. We are also examining changes in gene expression associated with oxidative stress and environmental chemical exposure.
The Cancer Biology Group at NIEHS focuses on early events in skin tumor development using a transgenic mouse model (TgAC). This model possesses a v-Ha-ras transgene under the regulation of a fetal globin promotor integrated at an ectopic site which confers a unique phenotype of inducible skin papillomas with a high rate of progression to invasive squamous and spindle cell neoplasms. The goals of our studies are to identify and characterize: 1) The cellular origin of the tumors and 2) critical genes which are involved in ras-mediated tumor induction and progression. Conventional cancer therapies have until recently depended on treatment late stages of tumor growth and involved non-specific mechanisms of cellular injury. By focusing on understanding early events in tumor induction we hope to gain insights into targets for intervention that can more specifically inhibit cancer cell growth.
Our laboratory uses the mouse as a model to study phenotypes with complex etiologies contributed by genetic and environmental factors and that underlie differences in susceptibility to common diseases. Genetics and a broad range of genomic, bioinformatic and computational tools are used in a new integrative field called systems genetics. Through many collaborative interactions, major research foci are currently in development, reproduction, neurobiology, cancer (colon and breast), cardiology, exposure biology and computational genetics. Our laboratory is also investigating the function role of the Egfr/Erbb gene family of receptor tyrosine kinases through embryonic stem cell manipulation, transgenics, gene targeting and other genetic engineering technologies.
Topics include gene discovery, genomics/proteomics, gene transcription, signal transduction, molecular immunology. Disease relevant issues include infectious diseases, autoimmune and demyelinating disorders, cancer chemotherapy, gene linkage.
Blood Flow and Endothelial Cell Function. We are interested in how vascular endothelial cells signal and respond to blood flow in the context of cardiovascular disease and tumor progression.
We study mechanisms of cancer using cutting edge technologies - genetically engineered mice, microscopy, genomics, cell culture and more. We have developed many models cancer and have made major contributions on the functions of p53, pRb and PTEN.
How the loss of different components of the SWI/SNF complex contributes to neoplastic transformation remains an open and important question. My laboratory concentrates on addressing this question by the combined use of biological, biochemical and mouse models for SWI/SNF complex function.
My laboratory is interested in characterizing the role of cytoplasmic signal transduction pathways in regulation of androgen receptor activity and progression of prostate cancer. Our studies have focused on HER-2 receptor tyrosine kinase and we have demonstrated that HER-2 activation stimulates androgen receptor activity and HER-2 inhibition inhibits androgen receptor transcriptional function at the level of recruitment to the androgen responsive enhancers. These findings have led to the design and initiation of the protocol involving lapatinib, a clinical HER-2 inhibitor, in treatment of patients with prostate cancer. More recently, we have demonstrated that activated Cdc42-associated kinase Ack1 promotes progression of prostate cancer via tyrosine phosphorylation of androgen receptor at Tyr-267 and Tyr-363
residues. We are interested in further characterizing the role of tyrosine phosphorylation of androgen receptor in prostate cancer and development of Ack1 targeted therapy for clinical use.
Our work focuses on molecular aspects of androgen receptor regulation of gene expression, which includes coactivator interactions with the androgen receptor and its functional importance in various clinical syndromes.
Using genetic, cell biology, biochemical and proteomic approaches to determine the function and mechanism of - (1) CDK inhibitors in development and tumor suppression, (2) the p53 degradation and transport, and (3) RING family of ubiquitin ligases.
The site of microtubule attachment to the chromosome is the kinetochore, a complex of over 60 proteins assembled at a specific site on the chromosome, the centromere. Almost every kinetochore protein identified in yeast is conserved through humans and the organization of the kinetochore in yeast may serve as the fundamental unit of attachment.
More recently we have become interested in the role of two different classes of ATP binding proteins, cohesions (Smc3, Scc1) and chromatin remodeling factors (Cac1, Hir1, Rdh54) in the structural organization of the kinetochore and their contribution to the fidelity of chromosome segregation.
We employ modern technologies - genomics, proteomics, mouse models, multi-color digital imaging, etc. to study cancer mechanisms. We have made major contributions to our understanding of the tumor suppressor ARF and p53 and the oncoprotein Mdm2.
Our lab is interested in how dynamic changes in chromatin structure affect gene expression, cell lineage determination and cancer development. Currently, we are focusing on two epigenetic modifications, DNA methylation and histone methylation.
