2010 St Jude Summer Plus Faculty
Departments of Epidemiology and Cancer Control
THE EFFECTS OF ANKLE FOOT ORTHOSES ON GAIT EFFICIENCY IN CHILDREN WITH ACUTE LYMPHOBLASTIC LEUKEMIA AND FOOT DROP
Kirsten K. Ness, PT, PhDBrief Overview: This study is designed to see if children with acute lymphoblastic leukemia who have developed foot drop during treatment for their leukemia consume less oxygen when walking with or without an ankle brace designed to support their foot during walking. In this study children with foot drop are asked to walk for six minutes without the brace on, rest, and then walk six minutes with the brace on. During the walk, the amount of oxygen used is measured. The child wears a face mask which is attached to the cart.
The amount of oxygen used during the walk with the brace on will be compared to the amount of oxygen used with the brace off.
The following would be learnt during the project:
Anthropometric Measurement for Research
Sensory Evaluation for Research
Flexibility Evaluation For Research
Muscle Strength Testing For Research
Cardiac Stress Testing/ECG Reading
Balance and Vestibular Testing For Research
Standard Mobility Evaluation
Clinical Outcome Study Design Techniques
The project is best suited to someone interested in Physical Therapy or Exercise Physiology.
Department of Immunology.jpg)
Helen Beere, PhD
DOES HEAT SHOCK FACTOR-1 CONTRIBUTE TO CANCER?
Transcription factors are proteins the regulate gene expression. Heat shock factor-1 (HSF-1) is a transcription factor that controls the expression of heat shock proteins (Hsps). These proteins help to protect cells against the harmful effects of DNA damage and genes that can cause cancer (oncogenes) by regulating signals that are involved in cell division and cell survival. Tumor cells often have increased expression of Hsps and in patients this is associated with resistance to cancer treatments such as radiation and chemotherapy. We wish to determine if HSF-1 and Hsps are required to enable tumor cells to survive and if they are, which signaling pathways they regulate to have this effect. We therefore propose to test if and how HSF-1 and Hsps contribute to the survival and resistance of tumor cells using cells that have no or increased expression of these potentially important proteins.
Techniques that will be used:
Tissue culture of primary cells and cell lines
Expression and purification of plasmid DNA
Transfection of cells (introduce genes into cells to change their behavior)
Treatment of cells to induce DNA damage
Immunoblotting to detect protein expression
Real time pcr to detect gene expression
Department of Infectious Diseases
Jonathan A. McCullers, MD
In general, I am interested in studying pathogenesis of influenza viruses with an eye towards developing interventions to ameliorate or prevent disease. The emergence of a new pandemic virus, the H1N1 swine-origin strain, has created an opportunity for translational research into the pathogenesis of this virus, its effects on normal children as well as the immunocompromised host, and means of treatment and prevention. My laboratory is currently conducting 4 clinical trials in patients at Le Bonheur and St. Jude with H1N1 infection or pneumonia. We are interested in understanding the etiology and outcomes of pneumonia, particularly in the setting of co-infections with H1N1 influenza, as well as in studying immune responses to H1N1 pandemic vaccine.
Students entering the laboratory will be given their own project within the overall umbrella of these studies. They will learn basic techniques used to cultivate and characterize influenza viruses and pathogenic bacteria, will employ advanced immunologic methods used to assess immune responses to these organisms or vaccines against these pathogens, and may study specific hypotheses in relevant animal models of disease. Students must be willing to get a flu shot and to complete humans subjects protection training.
Other projects ongoing in the lab can be found here:
http://www.stjuderesearch.org/mccullers/
Department of Molecular Pharmacology
Philip M. Potter, PhD
My laboratory’s research program focuses on the use of carboxylesterase enzymes (CE) to selectively activate anticancer drugs in tumor cells. If successful, these approaches should result in selective toxicity to the tumor, while sparing normal cells from the side effects of the drugs. CEs are efficient at activating the anticancer drug CPT-11, a highly effective drug that is currently used for colon cancer. As CPT-11 has demonstrated remarkable activity towards childhood solid tumors, increasing the activation of this agent should result in increased potency of the drug. Several different approaches have been applied to maximize CPT-11 activation including delivery of the CEs to tumor cells by adenovirus, antibodies and neural stem cells. Our goals are to continue to characterize the most efficacious route of CE delivery and to evaluate the preferred enzyme for use in animal studies.
A second area of research is the development of specific CE inhibitors. Since numerous drugs (e.g. heroin, cocaine, Tamiflu, CPT-11, etc) are hydrolyzed by CEs, selective inhibition of these enzymes may change the metabolism and hence the half-life of the drug in vivo. This may ultimately reduce the side effects associated with drug treatment, or alternatively make the drugs more effective. Our lab has recently identified selective CE inhibitors and we are currently assessing whether these compounds will be suitable for use in preventing drug hydrolysis both in cell culture and animals. If so, these inhibitors might be combined with currently used agents to prolong the availability of the drugs. Hence studies will be performed to determine whether the inhibitors are able to enter cells and inhibit CEs intracellularly, and to assess drug metabolism in mice treated with these compounds. Overall, both of these projects will use molecular biology, biochemistry, chemistry and cell biology techniques to address important questions in drug metabolism and antitumor activity.
Department of Oncology
Mari H. Dallas, MD
The Dallas lab is focused on improving the outcomes of patients undergoing hematopoietic stem cell transplant (HSCT) using umbilical cord blood (UCB) as an alternative stem cell source. H SCT using stem cells from a human leukocyte antigen (HLA) matched donor is a widely accepted form of therapy for various malignant and non-malignant hematological diseases. However, many patients do not have an HLA-matched donor identified. The use of UCB have certain advantages and disadvantages compared to bone marrow or peripheral blood stem cells. Our lab is interested in ex-vivo manipulation and culture of cord blood progenitors that may ultimately have therapeutic potential. Currently, we have three main focuses of the lab.
- Understanding the unique immunological interactions and barriers involved in cord blood transplantation. In particular the biology of regulatory T cells and antigen presenting dendritic cells. We use unique humanized immunodeficient mouse models, where a human thymic tissue is implanted in the kidney capsule to investigate the immune recovery after transplantation.
- Ex-vivo expansion of pluropotent hematopoietic stem cells using the Notch signaling pathway.
- Ex-vivio manipulation of cord blood progenitors using gene therapy to improve engraftment.
Participants of the Rhodes College Summer Plus Program will be actively involved in our laboratory team. Depending on the student’s interest, I have identified few well-defined projects that can be accomplished during this research period. The techniques that will be learned include and not limited to:
- Cell culture
- Cord blood hematopoietic stem cell isolation
- Microscopy and imaging of cells culture and tissue
- Involvement in murine transplantation and surgery
Department of Pharmaceutical Sciences
William E. Evans, PharmD
Research in the Evans’ lab is focused on the pharmacogenomics of anticancer agents, with an emphasis on childhood acute lymphoblastic leukemia (ALL) (reviewed in Evans and Relling, Science 1999; Evans and Relling, Nature, 2004; Pui and Evans, NEJM, 2006). Several approaches are currently being used to identify genes and genetic polymorphisms or copy number variations that are important determinants of the disposition and effects of antileukemic agents, including the interrogation of candidate genes (Krynetski and Evans, Am J Hum Gen, 1996) and the application of genome wide approaches such as gene expression profiling of leukemia cells and genomewide SNP mapping of patient cohorts that have been uniformly treated and evaluated on prospective clinical trials at St. Jude Children′s Research Hospital (reviewed in Evans and Relling, Nature, 2004). The lab comprises a number of post-doctoral fellows, research technologists, bioinformaticists, computer scientists and students, working with clinical collaborators and colleagues at St. Jude (physicians, clinical pharmacists, research nurses and other staff). The lab also has ongoing collaborations with investigators at other institutions in the US and Europe. Our overall goals are to elucidate genomic determinants of toxicity and efficacy of anticancer agents and translate this knowledge into new diagnostics and treatment strategies to optimize the therapy of ALL.
A summer student will participate in one of our ongoing studies investigating genes that we have linked with resistance to antileukemic agents (Holleman et al, NEJM, 2004; Lugthart et al, Cancer Cell, 2005). Techniques used in these studies include cell culture, Western blotting, DNA transfer, shRNA knockdown, plasmid production, and in silico genomic analysis.
The research mission of the Pharmaceutical Sciences Department at St. Jude is to discover the mechanisms that account for differences among patients in how they respond to medications, with specific emphasis on medicines for children with cancer and other catastrophic diseases. Much of the work of my laboratory our work focuses on finding the genetic basis of why patients and their tumor cells differ from one another. We also study how nongenetic factors (e.g., diet and drug interactions, kidney and liver function, and age) affect how patients differ from each other in response to medications. Our lab studies childhood acute lymphoblastic leukemia; the two phenotypes we study the most are relapse and glucocorticoid-induced osteonecrosis. There are substantial opportunities in computational biology, as we use genome-wide approaches to interrogate genetic variability. We also use chemical analyses (e.g. HPLC, LC/MS) to study medication pharmacokinetics, cell culture models, molecular biologic techniques, murine models, and analysis of clinical outcomes and phenotypes.
Department of Radiological Sciences
Claudia Hillenbrand PhD
Magnetic resonance imaging (MRI) can produce images non-invasively that reveal the morphology, metabolism, and function of internal tissues or organs. The impact of this technique on diagnostic radiology has been revolutionary in the past two decades because of its capability to produce anatomical images with unprecedented quality and soft-tissue contrast, its capacity to generate images in arbitrary orientation and determine entire volumes, and its lack of toxicity for the patient. However, what really is fascinating and attractive about MRI is its versatility and flexibility: the wide range of obtainable image contrasts and the possibility to create techniques which facilitate the acquisition of diagnostic, ultra-fast high resolution images with combined anatomical, metabolic, and functional information.
The MR Physics Lab aims to develop and validate advanced magnetic resonance imaging techniques. The team works on MR methods to acquire functional information from different organs in patients with sickle cell disease and cancer. We want to provide physicians with accurate and effective tools for non-invasive assessment of disease (e.g., organ vitality/damage) and treatment outcome. Our current organs of interest are the brain, the kidneys and the liver.
Important projects currently under way are: (a) the vascular assessment of the brain including development and validation of sensitive and quantitative methods for perfusion imaging, and development of advanced methods for time resolved flow quantification. (b) Functional assessment of kidney function. This involves the development of non-invasive perfusion methods and strategies to compensate or minimize effects due to the breathing motion. (c) Non-invasive quantitative assessment of liver iron content in patients with transfusional iron overload.
The Rhodes Summer Plus Student will actively work on either (b) or (c), depending on personal preference. For (b) the student will work on image segmentation algorithms that facilitate the volume determination of kidney compartments. He/she will implement post processing algorithms for renal perfusion quantification and display of vessels. The combination of information gathered from these steps will guide the student towards the development of improved visualization tools for display of merged information (e.g. perfusion map with overlaid vessel density map) and ultimately allow to assess the risk for future ischemic events (e.g. by documentation of serial reduction in perfusion and related measures of small vessel density). For (c) the student will develop model fitting algorithms for the quantitative assessment of iron overload especially in massively overloaded patients. Specifically this will include the selection and implementation of algorithms for phase unwrapping of complex MR data sets, and the utilization and characterization of model fitting functions needed to quantitatively describe the decay of the MR signal as a function of the liver iron content.
The interested student will work as member of a multi-disciplinary team consisting of MR Physicists, Radiologists, Hematologists, Oncologists, Biomedical Engineers, and Computer Scientists in the
The principal focus of our efforts in Molecular Imaging Research is the development of novel radiopharmaceuticals and imaging methods for the evaluation and management of children with tumors using positron emission tomography (PET). PET is a medical imaging method that can be used to investigate specific aspects of tumor biochemistry and pathophysiology. Individual projects will combine Organic Chemistry, Radiochemistry, Biochemistry and Pharmacology and internship opportunities are available in any or all of these areas. A typical project involves the synthesis of precursor molecules for radiolabeling and analytical standards, determination of optimal conditions for radiolabeling with carbon-11, fluorine-18 or other PET radionuclides, biochemical evaluation of the mechanism of action of the new radiopharmaceutical and biological testing in animal models of human disease. Project will involve some handling of radioactivity and experimental animals. Students are encouraged, but not required, to participate in these activities.
Specific research projects include: development, in collaboration with researchers at the University of Michigan, of C-11 labeled agents for imaging pheochromocytoma and neuroblastoma, radiolabeling an anti-neuroblastoma antibody in production at the St Jude GMP facility, radiolabeling to determine the in vivo trafficking of novel therapeutic nanoparticles, and design of radiotracers for measuring enzymatic activity involved in activation of a chemotherapeutic currently under development.
Department of Structural Biology
Eric J. Enemark, PhD
DNA replication machinery
DNA replication is a fundamental process for all organisms. We are interested to learn structural and mechanistic information about how two complementary DNA strands are separated from each other so that they may be copied. We are investigating the atomic structure of the MCM complex, a molecular machine that is responsible for unwinding DNA strands during replication, and how this complex interacts with DNA. A major component of this work is visualization of the interaction(s) between MCM proteins and DNA through X-ray crystallography.
A Summer Plus student will have the opportunity to participate in several phases of a structural project, including: generation of protein expression constructs through PCR and other molecular biology techniques, overexpression of target proteins in a host organism, purification of target proteins by affinity and other chromatographic methods, and conduction of crystallization trials.
Richard W. Kriwacki, PhD
PUMA-induced dimerization of BCL-xL promotes p53-dependent apoptosis
Following genotoxic stress, nuclear p53 induces the expression of PUMA (p53 upregulated modulator of apoptosis), a BH3-only protein that binds and inhibits antiapoptotic BCL-2 proteins, including BCL-xL. Structural investigations of PUMA and the BCL-xL·PUMA BH3 domain complex by NMR spectroscopy and X-ray crystallography reveal a novel, PUMA-induced carboxyl-terminus domain swap dimerization of BCL-xL that depends upon a p-stacking interaction between PUMA W133 and BCL-xL H113. Prior to interaction, PUMA is intrinsically disordered, allowing W133 and BH3 domain residues to interact with BCL-xL, triggering its dimerization. PUMA and PUMA W133A equivalently inhibit anti-apoptotic BCL-2 proteins to sensitize for TNF-induced apoptosis, but only wild type PUMA promotes DNA-damage induced apoptosis. Biochemical and cellular data suggest PUMA-induced structural remodeling of BCL-xL modulates its affinity for cytosolic p53, thus promoting p53-dependent BAX activation and apoptosis. These results provide mechanistic insights into the consequences of protein·protein interactions within the BCL-2 family.
The Kriwacki lab recently received a new NIH grant on this project and an undergraduate student would participate in continuing studies to determine the structural features of the BCL-xL/p53 complexes. An important unanswered question is how BCLxL dimerization causes p53 release after PUMA binding. An additional unanswered question is how cancer-associated mutations in p53 affect its interactions with BCL-xL and other BCL-2 family proteins which cooperate to regulate the intrinsic pathway of apoptosis. An undergraduate student would learn basic techniques such as protein expression and purification, as well as how to perform protein-protein interaction assays using calorimetry, fluorescence and NMR spectroscopy. Ultimately, mechanistic insights gained from biophysical investigations would be translated to functional assays of apoptosis in cells.
In our laboratory, structural and biophysical methodologies, especially NMR spectroscopy, are used to investigate the molecular mechanisms underlying the specific regulatory and targeting interactions of the intracellular signaling pathways. Expertise in the laboratory in which trainees will receive instruction includes solution protein NMR spectroscopy, lignad-protein, protein-protein interaction, protein expression and purification, and structure-based drug design.
Currently, the WNT pathway is one of the major focuses in our laboratory. Wnt signaling plays an important role in embryonic development and in regulation of cell growth. Inappropriate activation of the Wnt pathway has been shown to lead to several cancers, including childhood cancers such as medulloblastoma and Burkitt lymphoma. Recently, we have worked to develop small-molecule inhibitors that target the protein– protein interactions alone the Wnt signaling pathway for use in the elucidation of biological processes and as potential cancer-treatment and prevention agents.
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