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Biomedical - Cancer • Hypoxia
Cancer
Identification of new targets for cancer therapy through bioinformatics will be the focus of this group. The oncology research
provides a good example of the bioinformatics/functional genomics program. A potential gene target for cancer is identified
using bioinformatics. "Hits" are validated in the wet lab by immunocytochemistry and cell culture and further validated in
animal models. The function of the gene target in normal as well as abnormal or diseased cells can be identified through
methodologies used in transgenic technology, Affymetrix GeneChip® technology and physiological analysis. These latter properties
fall well within the expertise of the faculty and members of the Center for Molecular Biology and Biotechnology at FAU.
This approach has led to: (1) the discovery of two gene targets for colon cancer and other cancers and the formation of
a start up biotechnology company, Forseti Biosciences, Inc., at FAU; and (2) the identification of extracellular matrix
proteins and enzymes that aid in melanoma progression, and the development of therapeutic agents against and diagnostic
agents for these proteins and enzymes. These therapeutic agents were used in the founding of Biostratum, Inc., while
diagnostic agents are currently marketed by Bachem Biosciences, Peptides International, Calbiochem/Novabiochem, and R&D Systems.
As part of these studies, a repository of cDNAs from a statistically significant number of matched pairs of cancer and
normal tissues (from the same patient) involving major types of cancers has been established at FAU, and continues to
be developed. The Center will obtain tumor tissues from local community hospitals and the federally supported Cooperative
Human Tissue network. The cDNA libraries from these matched sets of tumor and normal tissues will be critical for
establishing relevance for the chosen genes from bioinformatics approaches. This repository will enable the cancer researchers
at FAU and elsewhere to prioritize the genes emerging from the sequencing efforts and hence go to the next step of establishing
functional genomics for the most promising targets. This repository has proved invaluable in the identification of two highly
cancer specific markers which were validated for functional genomics studies. The validation employed modern approaches in cell
and molecular biology including antisense technology, elucidation of signal transduction pathways and mechanism of cell death
by apoptosis. The targets thus identified will be proposed for diagnostic marker development working together with local and
national industries and the Federal Government. Using Affymetrix GeneChip® technology, a genetic fingerprint or gene expression
profile selective to individual cancers can be established. This technology is already established at FAU, which recently
received $567 thousand as an appropriation to purchase an Affymetrix GeneChip machine to support its functional genomics
program -- one of only two in the State of Florida. Students will be trained in this area, enabling them to develop skills
in the technology that will help them prepare for the competitive job market.
In other studies, gene expression arrays will be used to investigate the regulation of the vascular endothelial growth factor
gene, which has been identified as an important factor that controls cancer cell growth and mestastasis via promoting
tumor angiogenesis.
Hypoxia
The Center has a unique concentration of expertise in the area of hypoxia and will focus on examining hypoxia-related stresses
in disease and aging. The research theme incorporates functional genomics to elucidate the molecular and physiological
mechanisms of stress tolerance with potentially far-reaching consequences in the biomedical field. The premise is that hypoxia
and tissue-generated reactive oxygen species (ROS) are common causative agents for many important pathologies such as stroke,
heart attack and age-related degeneration. The novel approach of this group is to employ unique animal models that are protected
against anoxia (turtle, carp) and animal models of neuro-degenerative disease and aging (drosophila, mouse, turtle) to investigate
their physiological and molecular defense mechanisms.
A halt in the oxygen supply to the brain or heart can quickly lead to cardiac failure (heart attack) and neuronal death (stroke).
The brain in particular is extremely sensitive to reduction of oxygen availability and suffers energy failure and consequent
irreversible damage within minutes of ischemia. In contrast, the turtle brain uniquely can survive days of anoxia. This is
achieved by activating processes that cause a severe depression in turtle brain metabolic demand. The mechanisms involved
include down-regulating ion channel activities, the enhancement of brain inhibitory processes and the suppression of excitatory
processes.
To understand the molecular adaptations that mediate cellular survival in hypoxia studies, research programs at FAU have
determined patterns of transcription and protein expression for a range of key molecular targets in the turtle including stress
and heat shock proteins, immediate early gene-transcription factors and components of the apoptotic machinery. In particular,
the role of specific membrane ion channels in channel arrest is being investigated through transfection of dominant negative
gene constructs of specific ion channels. Antisense vectors and substrate binding assays will allow us to identify the involvement
of key signaling molecules.
Post-ischemic damage, injury that occurs after the blood supply is reinstated, is a serious complication in stroke-related
disease. The tissue damage seen during reperfusion is in large part due to the formation of ROS that react with nucleic acids,
proteins and lipids. Cells protect themselves against this oxidative damage by either: 1) destroying the ROS with enzymes such
as superoxide dismutase (SOD) and catalase or 2) repairing the damage done to the macromolecules. One of the repair mechanisms
under study at FAU involves a group of enzymes that are part of the methionine sulfoxide reductase (Msr) family. It is known that
ROS and reactive nitrogen species readily oxidize methionine (met) in cells, both free met and met residues in proteins. The
product of met oxidation is primarily methionine sulfoxide (met (o)), which in may instances results in loss of biological activity
of the protein. The Msr family of proteins are able to reverse this damage and appear to be an important mechanism cells use to
protect against oxidative damage. The use of this system to treat diseases that result from oxidative damage is the subject of
a recent FAU patent application.
A turtle brain is in a prime condition to experience massive ROS when it is reoxygenerated after hours of anoxia. As it survives
this insult, it either has mechanisms that protect against the formation of ROS and/or mechanisms to repair ROS damage. High
levels of tissue ascorbate and increased activity levels of SOD indicate that the turtle has an enhanced antioxidant capacity
compared to mammals.
One of the most important current paradigms of age-related diseases concerns the accumulative damaging effects of ROS, probably
due in part to the experience of intermittent bouts of hypoxia and reoxygenation throughout life and the loss of cellular
mechanisms to protect against oxidative damage. Age dependent changes in cellular function are known to involve programmed
changes in gene expression as well as oxidative damage to DNA, proteins and lipids through ROS accumulation. Age-related
increases in protein oxidation have been reported in a variety of tissue types including fibroblasts, brain cells, hepatocytes
and skeletal muscle. FAU studies on the molecular and physiological basis of ROS induced cellular stress and aging have employed
two animal models, one a drosophila transgenic strain that overproduces Msr and the second an inherently long-lived species of
the fresh water turtle. Both drosophila and the turtle are accepted models for aging studies by the National Institute of
Aging/National Institute of Health.
Center researchers hypothesize that a superior protection against ROS damage may confer defense against age-related diseases.
As outlined above, the turtle appears to be protective against ROS. Also, over expression of the MsrA gene resulted in dramatic
increase (>70%) in the life span of the flies. This life extension could be obtained by specific expression of the MsrA in
neuronal cells, suggesting that normal death in flies involves oxidative damage in the central nervous system. FAU studies on
the role of ROS in the cellular mechanisms of aging have two complimentary objectives.
1) The induction of cell death in brain cells isolated from turtle by intervening in specific ROS protection pathways.
2) The extension of drosophila life span by the enhancement via genetic or biological means of the methionine sulphoxide reductase system.
As a correlate to the studies on the relationship between ROS and aging, fundamental mechanisms of response to oxidative stress will
also be examined. There is considerable evidence relating zinc-dependent systems and protection against oxidative stress that
involves regulation of expression of several protective systems, notably metallothionein and glutathione. MsrB, a zinc-binding
selenoprotein recently identified in humans and drosophila, possesses Msr activity. Elucidating the nature of interactions that
exist among these apparently interrelated processes, using an approach based on functional genomics, is planned to shed light on
higher order processes associated with oxidative stress and aging.
The vision is that these studies will identify important and novel new targets for treatment of hypoxia-related diseases that will
be tested in the Center. The characterization of the defense mechanisms of these unique species will lead to clinical breakthroughs
in gene therapy and physiological intervention for stroke, myocardial ischemia and a variety of age-related disorders including
Parkinson's disease and Alzheimer's disease.
Two of the hypoxia and oxidative damage research programs have progressed to the point where there is commercial interest. The
studies related to cardiac ischemia and the effects use of gene therapy to protect against hypoxia and ischemic damage in this organ
are currently being supported by industry. The second program of commercial interest relates to neurodegenerative diseases and aging.
The studies on the role of Msr system in protecting against oxidative damage have led to possible novel ways that the system can be modulated.
Please CLICK HERE to view the biomedical team.
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