Pilot Projects - 2004

Pilot Projects
The Southwest Environmental Health Sciences Center (SWEHSC), an NIEHS funded Center at the University of Arizona, announces the availability of awards up to $30,000 for pilot projects involving research related to the mission of the National Institute of Environmental Health Sciences and the SWEHSC. Pilot projects are designed to provide support for obtaining preliminary data that can be used in developing major proposals for submission to extramural funding agencies. In this round of funding, priority will be given to projects involving translational research. All University of Arizona junior faculty are eligible to apply. The SWEHSC is particularly interested in applications from junior faculty who have not previously performed research in environmental health science, but who would be interested in broadening their research to include environmentally-related research.

Applications must make use of technologies available in the SWEHSC Facility Cores. Projects that provide for interaction with existing SWEHSC investigators are encouraged. Information about the SWEHSC and its resources can be found at http://swehsc.pharmacy.arizona.edu/index.html.

Pilot Project News
Pilot projects are designed to provide support for obtaining preliminary data that can be used in developing major proposals for submission to extramural funding agencies.

In the current round of funding, priority was given to projects involving translational research. The following three projects were funded:

Biochemical and bioinformatics studies on uranium toxicity of zinc finger proteins.
David Segal, Ph.D.
Uranium, a metal used in weapons and energy production, was known to cause renal toxicity similar to cadmium, but more recently has been shown to cause reproductive and developmental toxicity. C2H2 zinc finger domains constitute the most common type of protein structure in the human genome, and are found on a majority of proteins involved with gene regulation.

Zinc fingers derive their name from the fact that they fold around a zinc ion, which is required for stability. However, it has been shown that numerous other toxic metals, such as cadmium, can displace the zinc, leading to altered protein structure and loss of protein function. Dysregulation of gene expression has been linked to a variety of human diseases, including birth defects and cancer.

Disruption of gene regulation by inhibition of zinc finger function has been suggested to be an important mechanism of metal toxicity. Dr. Segal hypothesizes that uranium will also have inhibitory effects on zinc finger proteins.

This hypothesis will be investigated by performing zinc finger-DNA binding assays in the presence of zinc, uranium, and cadmium, under various reaction conditions. In vitro mixtures of purified zinc finger proteins, DNA, and metal will be analyzed using various DNA-binding assays. Altered metal occupancy by the protein will be verified by ICP-MS. Simultaneously, a bioinformatics study will investigate the involvement of zinc finger transcription factors in the regulation of genes whose expression is altered by uranium exposure.

CYP2E1: Role in the Hepatic Steatosis induced by Hydrazine.
Charlene A. McQueen, Ph.D.
Causes of nonalcoholic fatty liver disease (NALD) and nonalcoholic steatohepatitis (NASH) include obesity, weight loss, diabetes, drugs and environmental agents. The etiology and profession of damage is not well understood; however, when the mechanisms for lipid turnover are overwhelmed, oxidative stress and lipid peroxidation may lead to further cell damage and fibrogenesis.

Mitochondrial, microsomal and peroxisomal oxidations are sources of reactive oxygen species (ROS). CYP2E1 and CYP4A14 have been implicated in this process. Hydrazine (HD) is a compound that is hepatotoxic, causing steatosis, lipid peroxidation and depletion of ATP and GSH.

Although the mechanism by which HD induces liver damage is not fully elucidated, evidence suggests that cytochrome P450 isoforms including CYP2E1 play a role. The proposed studies will investigate the role of cytochrome P450s in the development and progression of hepatic steatosis and damage induced by HD. The hypothesis is that biotransformation of HD by CYP2E1 decreases steatosis and subsequent liver damage.

Role of epigenetic effectors on p53/BRCA-1 gene interactions in the etiology of sporadic breast cancer.
Donato Romagnolo, Ph.D.
Whereas suppression of estrogen receptor (ER) functions using selective estrogen receptor modulators (SERMs) such as tamoxifen has been shown to be useful in the treatment of breast cancer, remission of many ER-positive breast tumors is followed by acquisition of resistance to antiestrogens and disease relapse.

This fact suggests that changes in gene networks that control cell proliferation need to be considered in order to develop effective preventive strategies. The p53 gene encodes for a key player controlling cell cycle progression and apoptosis.

However, mutations in the coding sequence of p53 have been identified in approximately 30 to 50% of breast cancers. Polycyclic aromatic hydrocarbons (PAHs) are of particular importance as risk factors in breast cancer because a higher prevalence of p53 mutations have been found in breast tumors from smokers vs. non-smokers and the tumor tissue from smokers has been shown to contain higher levels of PAH signature mutations than the non-tumor tissue at hotspot codons 248, 273, 157, 158, and 245 in the p53 gene, which are among the most frequent point mutations in breast cancer populations.

The hypothesis to be tested is that exposure to PAHs leads to fixation of mutations at specific hotspots in the p53 gene. In turn, mutated p53 can no longer regulate BRCA-1 expression in mammary tissue. The loss of p53 and BRCA-1 functions leads to disruption of cell cycle checkpoints and accumulation of DNA damage, and ultimately to sporadic breast cancer.