title: Isolation and characterization of androgen receptor mutant, AR(M749L), with hypersensitivity to 17-beta estradiol treatment.
abstract: Estrogens, primarily 17beta-estradiol (E(2)), may play important roles in male physiology via the androgen receptor (AR). It has already been shown that E(2) modulates AR function in LNCaP prostate cancer cells and xenograft CWR22 prostate cancer tissues. Using a molecular model of E(2) bound-AR-ligand binding domain (LBD) and employing site-directed mutagenesis strategies, we screened several AR mutants that were mutated at E(2)-AR contact sites. We found a mutation at amino acid 749, AR(M749L), which confers AR hypersensitivity to E(2). The reporter assays demonstrate that E(2) can function, like androgen, to induce AR(M749L) transactivation. This E(2)-induced AR mutant transactivation is a direct effect of the AR(M749L), because the transactivation was blocked by antiandrogens. The hypersensitivity of AR(M749L) to E(2) is not due to increased affinity of AR(M749L) for E(2), rather it may be due to the existence of the proper conformation necessary to maintain E(2) binding to the AR-LBD long enough to result in E(2)-induced transactivation. AR(M749L) transactivation can be further enhanced in the presence of AR coregulators, such as ARA70 and SRC-1. Therefore, amino acid 749 may represent an important site within the AR-LBD that is involved in interaction with E(2) that, when mutated, allows E(2) induction of AR transactivation.
authors.affiliation: George Whipple Laboratory for Cancer Research Department of Pathology, University of Rochester, Rochester, New York 14642, USA.
authors.forename: Tin Htwe
authors.initials: TH
authors.lastname: Thin
authors.forename: Liang
authors.initials: L
authors.lastname: Wang
authors.forename: Eungseok
authors.initials: E
authors.lastname: Kim
authors.forename: Loretta L
authors.initials: LL
authors.lastname: Collins
authors.forename: Ravi
authors.initials: R
authors.lastname: Basavappa
authors.forename: Chawnshang
authors.initials: C
authors.lastname: Chang
mesh_terms: D000818:Animals; D001665:Binding Sites; D019556:COS Cells; D003907:Dexamethasone / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000494:pharmacology*; D017930:Genes, Reporter; D006801:Humans; D007700:Kinetics; D008024:Ligands; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D016133:Polymerase Chain Reaction; D011374:Progesterone / Q000494:pharmacology; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011944:Receptors, Androgen / Q000235:genetics*; D015398:Signal Transduction; D013256:Steroids / Q000378:metabolism; D015533:Transcriptional Activation; D014357:Trypsin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
chemical_list: D008024:Ligands; D011944:Receptors, Androgen; D013256:Steroids; D011374:Progesterone; D004958:Estradiol; D003907:Dexamethasone; D014357:Trypsin