Dominant Negative Mutants of the Estrogen Receptor as Probes of Estrogen Action and Inhibitors of Breast Cancer Growth
Annual rept. 1Jul 95-30 Jun 96
NORTHWESTERN UNIV EVANSTON IL
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Estrogen provides one of the most important growth stimulators for breast epithelium. There is emerging evidence for complex interactions between estrogen and other growth factors that are important for the growth of breast cancer cells. Growth factor signalling pathways stimulate estrogen responsive genes, perhaps via the estrogen receptor. These findings open new opportunities to block breast cancer cell growth using mutant receptors that function as antagonists. In year 1 of this project, we created a series of estrogen receptor ER mutants that were shown to function in a dominant negative manner. In year 2, we created more potent dominant negative ER mutants and developed a more selective estrogen-responsive reporter gene. We found that estrogen and growth factor signaling pathways are separable when studied with sensitive luciferase reporter gene assay. The effects of these dominant negative mutants are being evaluated in estrogen-dependent proliferation assays were in T47D breast cancer cells. Tetracycline-inducible ER expression vectors were created to allow induction of ER mutants in stably transfected cells. Preliminary results show potent inhibition of cell growth by mutant ERs. For transgenic studies, MMTV promoter-ER expression vectors have been created. Thus we have completed each of the goals as outlined in the original proposal.
- Genetic Engineering and Molecular Biology
- Anatomy and Physiology
- Medicine and Medical Research