NASA Scientific and Technical Aerospace Reports

Homeobox genes represent a class of transcription factors important in embryogenesis, organogenesis, cell growth and
differentiation and cell migration. However, there is little known about their role in regulating endothelial cell (EC) phenotype
in response to proangiogenic factors secreted by breast cancer, although at least two homeobox genes have been implicated
in inducing the angiogenic phenotype in ECs. We are therefore testing the homeobox gene Gax regulates breast cancer-induced
angiogenesis through its ability to regulate the expression of downstream target genes in ECs. Using an in vitro tube formation
assay, we have found that Gax expression inhibits in vitro angiogenesis. Moreover, by real time quantitative reverse
transcriptase PCR, we have found that Gax expression is downregulated by proangiogenic factors and, by cDNA microarray
analysis, that Gax downregulates pro- angiogenic adhesion molecules in ECs and upregulates the cyclin-dependent kinase
inhibitor P(19INK4D). In addition, we have observed that Gax expression downregulates NF-kB- dependent gene expression
in ECs and inhibits the binding of NF-kB to its consensus sequence These observations will allow us to study the mechanism
of Gax-mediated activation or repression of their expression to be studied and will form the basis for future studies that will
examine in more detail the mechanism by which Gax activates downstream target gene and the detailed signaling pathways
involved in this activation. Given the profound effect Gax has on endothelial cell activation, it is likely that these studies will
identify new molecular targets for the antiangiogenic therapy of breast cancer. Ultimately, these same techniques will be
applied to other homeobox genes implicated in regulating EC phenotype during breast cancer-induced angiogenesis.
DTIC
Cancer; Endothelium; Mammary Glands
20040111731 Medical Univ. of South Carolina, Charleston, SC
A Functional Genomics Approach to Understanding and Evaluating Health in Navy Dolphins
Romano, Tracy A.; Warr, Gregory; Aug. 2004; 6 pp.; In English
Contract(s)/Grant(s): N00014-02-1-0386
Report No.(s): AD-A425901; No Copyright; Avail: CASI; A02, Hardcopy
The U.S. Navy maintains and deploys approximately 70 bottlenose dolphins for military operations and research. Health
maintenance of these animals is critical to the success of the Navy’s mission. Functional genomic approaches offer the
potential to complement traditional methods of health assessment with rapid, sensitive and highly discriminative tests for
health, infection, and exposure to chemical, biological and physical stress. To this end we have initialized development of a
dolphin gene microarray in order to evaluate its utility as a transcriptomic biosensor in the health assessment of dolphins. To
this end, normalized dolphin cDNA libraries have been generated from stimulated and unstimulated dolphin peripheral blood
leukocytes. Expressed sequence tags (ESTs) have been collected and sequenced. Target genes (both immune response and
stress-related) have been amplified and segments cloned for subsequent microarray development as well as for cloning of the
full-length genes. The immunoglobulin genes were further studied and characterized at the molecular level. These valuable
molecular tools will not only help in characterization of the dolphin immune system, but will be utilized in the development
of a dolphin gene microarray to use as a transcriptomic biosensor in the health assessment of Navy and wild dolphins.
DTIC
Dolphins; Genetic Engineering; Health; Navy
20040111732 Nebraska Univ., Omaha, NE
The Role of KSR-Associated Kinases in Breast Cancer Signaling
Schreiner, Steven J.; Lewis, Robert; Feb. 2004; 8 pp.; In English
Contract(s)/Grant(s): DAMD17-00-1-0360
Report No.(s): AD-A425902; No Copyright; Avail: CASI; A02, Hardcopy
Kinase Suppressor of Ras 1 (KSR1) is a putative scaffold of the Raf/MEK/ERK kinase cascade. Elevated activity of this
mitogenic kinase cascade is a critical stimulus for the proliferation of many human cancers including malignant breast
carcinomas. We examined the effects that KSR1 expression has on different cellular processes, including proliferation, cellular
response to growth factor stimulation (i.e. PDGF, EGF), differentiation of fibroblasts into adipocytes, senescence,
transformation by oncogenic Ras, and cell motility. The level of KSR1 expressed within cells appears to control cell fate, as
very high level of KSR1 expression leads to cell proliferation and a significant reduction in cell motility, while a lower level
of expression allows cells to differentiate. KSR1 therefore may serve the role of a pseudo rheostat that directs the dominant
cellular processes that control cell fate. The biological mechanism of this regulation may reside in the phosphorylation of
KSR1, as KSR1 is phosphorylated on at least 15 residues in intact cells, and alteration of KSR1 phosphorylation results in
altered subcellular localization, enhanced activation of ERK, and increased RasV12-induced anchorage-independent growth.
The exact role of KSR1 may be in the control of biological processes that regulate cytoskeletal organization, based on the
findings that KSR1 can interact with three cytoskeletal modulating proteins, FHOS, FHL3, and Flightless I, and the
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