Funded Grants

Investigating the Biological Function of the Glioma Associated Gene SETA

The prognosis for astrocytic glioma is dismal: post-operative survival of a patient with glioblastoma multiforme, the most aggressive form of this disease, is often not more than a year. Furthermore, life expectancy has not significantly improved in the last decade in spite of refinements in diagnosis, surgery, and adjuvant therapy. What has been achieved is an increased understanding of the molecular events that underlie these tumors, and the hope is that this will lead to the new therapies that are urgently needed. One route to new treatments is via the identification of genes that satisfy three criteria: [I] expression of the gene is restricted to the tumor; [2] gene products drive the proliferation, survival and/or invasion of tumor cells; [3] gene products can be inhibited by pharmacologically suitable molecules.

The SETA (SH3 domain encoding, !expressed in tumorigenic astrocytes; SH3 is src homology region 3) gene, which is the focus of this research proposal, has the potential of satisfying all three criteria. As described in Preliminary Data (see page 7) expression studies at the mRNA level show that SETA is found in experimentally induced rat gliomas, and human tumors, but not in the normal adult brain. Furthermore, the rodent SETA protein is expressed in cultured astrocytes when they acquire the ability to form tumors. These data suggest that SETA expression correlates with tumor formation, and so satisfies the first criterion. To determine the role of the SETA protein in glioma biology the following specific aims are proposed:

1. Isolation and characterization of the human SETA gene

i. Cloning of the human SETA gene.

ii. Generation of antibodies against the human SETA protein.

iii. Analyzing human brain tumor sections with anti-SETA antibodies

2. Examining the biological role of SETA protein(s) by misexpression

i. Making of SETA misexpression constructs.

ii. Establishing SETA misexpressing cell lines.

iii. Characterizing the impact of SETA misexpression on cell phenotype.

iv. Studying the posttranslational modification of SETA proteins.

3. Identifying molecules that interact with SETA protein(s) via SH3 domains

i . Co-immunoprecipitation of SETA binding proteins

ii. Cloning of SETA-binding proteins using a yeast two-hybrid approach.

iii. Identifying the consensus sequence of peptides that bind SETA SH3 domains by phage display library screening.

The successful outcome of the proposed studies would represent an important step towards the potential exploitation of an interesting novel gene for clinical benefit to brain tumor patients. Understanding the molecular interactions SETA participates in, will also point to ways of inhibiting its function, for example via the SH3 domains '.