title: Alien interacts with the human androgen receptor and inhibits prostate cancer cell growth.
abstract: Prostate cancer cell growth is initially androgen dependent. Androgen antagonists are used in prostate cancer therapy to inactivate the transcriptional activity of the human androgen receptor (hAR) and to inhibit the proliferation of prostate cancer. Here, we have characterized Alien with characteristics of a corepressor as a novel interacting factor for the antagonist bound hAR. Alien is recruited to hAR in the presence of the AR antagonist cyproterone acetate (CPA). The interaction of Alien with hAR is verified in vivo and in vitro by a modified mammalian two-hybrid system, coimmunoprecipitation, chromatin immunoprecipitation, and in vitro binding assays. In contrast to other nuclear receptors, Alien binds to the amino-terminus of hAR with the receptor SUMOylation (small ubiquitin modifier) sites being involved. Furthermore, cellular localization of Alien is changed towards a predominant nuclear localization upon treatment of prostate cancer cells with CPA. Notably, stable expression of Alien in LNCaP cells inhibits both endogenous prostate-specific antigen expression and proliferation of these cells in the presence of CPA but not in the presence of an AR agonist. These findings underline the importance of corepressors for inhibition of prostate cancer cell growth by androgen antagonists.
authors.affiliation: Department of Medicine, Institute of Human Genetics and Anthropology, Kollegiengasse 10, 07743 Jena, Germany.
authors.forename: Udo
authors.initials: U
authors.lastname: Moehren
authors.forename: Maria
authors.initials: M
authors.lastname: Papaioannou
authors.forename: Christina A
authors.initials: CA
authors.lastname: Reeb
authors.forename: Wei
authors.initials: W
authors.lastname: Hong
authors.forename: Aria
authors.initials: A
authors.lastname: Baniahmad
mesh_terms: D000726:Androgen Antagonists / Q000494:pharmacology; D000728:Androgens / Q000502:physiology; D002455:Cell Division / Q000187:drug effects; D017373:Cyproterone Acetate / Q000494:pharmacology*; D006801:Humans; D008297:Male; D020411:Oligonucleotide Array Sequence Analysis; D010957:Plasmids; D011471:Prostatic Neoplasms / Q000473:pathology* / Q000517:prevention & control; D012333:RNA, Messenger / Q000235:genetics; D011944:Receptors, Androgen / Q000235:genetics / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection
chemical_list: D000726:Androgen Antagonists; D000728:Androgens; D012333:RNA, Messenger; D011944:Receptors, Androgen; D017373:Cyproterone Acetate