A30
Shedding light on estrogen receptor alpha-cofactor interactions
Madryn Lake1, Quang-de Nguyen2, Simak Ali1, Eric O Aboagye2
1Imperial College London, London, UK, 2Comprehensive Cancer Imaging Centre, Imperial College London, London, UK, 3Charing Cross Hospital, Imperial College Healthcare NHS Trust, London, UK
Estrogens have been implicated in the initiation and progression of breast cancer. Estrogen signals through the estrogen receptor (ER), a nuclear receptor transcription factor, whose activity is regulated by ligand specific interactions with coactivator and corepressor proteins.
Distinct ER-cofactor interactions are believed to be responsible for the tissue specific actions of selective estrogen receptor modulators (SERMs) and changes in ER-cofactor interactions are thought to be involved in the development of endocrine resistance.
Transient ER: coregulator interactions are difficult to study in vivo; the aim of this project is to image these interactions using a split luciferase complementation assay.
Luciferase fragment fusion protein constructs have been produced for full length ERα and its coactivator AIB1 in addition to truncated interacting domain constructs containing the ERα ligand binding domain (ERα-LBD) and AIB1 nuclear receptor interaction domain (AIB1-RID).
Transient transfection of these constructs has shown a reversible estrogen-induced increase in luciferase activity which can be modulated by antiestrogens; illustrating the potential for visualization of dynamic ER-AIB1 interactions using this assay. Constructs are currently being optimized before stable cell lines are produced to investigate these interactions in vivo using a xenograft model.
