title: CCDC62/ERAP75 functions as a coactivator to enhance estrogen receptor beta-mediated transactivation and target gene expression in prostate cancer cells.
abstract: Human prostate cancer (PCa) and prostate epithelial cells predominantly express estrogen receptor (ER) beta, but not ERalpha. ERbeta might utilize various ER coregulators to mediate the E2-signaling pathway in PCa. Here, we identified coiled-coil domain containing 62 (CCDC62)/ERAP75 as a novel ER coactivator. CCDC62/ERAP75 is widely expressed in PCa cell lines and has low expression in MCF7 cells. Both in vitro and in vivo interaction assays using mammalian two-hybrid, glutathione S-transferase pull-down and coimmunoprecipitation methods proved that ERbeta can interact with the C-terminus of CCDC62/ERAP75 via the ligand-binding domain. The first LXXLL motif within CCDC62/ERAP75 is required for the interaction between ERbeta and CCDC62/ERAP75. Electrophoretic mobility shift assay showed that CCDC62/ERAP75 can be recruited by the estrogen response element-ER complex in the presence of ligand. Furthermore, a chromatin immunoprecipitation assay demonstrated the hormone-dependent recruitment of CCDC62/ERAP75 within the promoter of the estrogen-responsive gene cyclin D1. In addition, using silencing RNA (siRNA) against endogeneous CCDC62/ERAP75, we demonstrated that inhibition of endogenous CCDC62/ERAP75 results in the suppression of ERbeta-mediated transactivation as well as target gene expression in LNCaP cells. More importantly, using the tet-on overexpression system, we showed that induced expression of CCDC62/ERAP75 can enhance the E2-regulated cyclin D1 expression and cell growth in LNCaP cells. Together, our results revealed the role of CCDC62/ERAP75 as a novel coactivator in PCa cells that can modulate ERbeta transactivation and receptor function.
authors.affiliation: Department of Urology, University of Rochester Medical Center, Rochester, NY 14642, USA.
authors.forename: Ming
authors.initials: M
authors.lastname: Chen
authors.forename: Jing
authors.initials: J
authors.lastname: Ni
authors.forename: Hong-Chiang
authors.initials: HC
authors.lastname: Chang
authors.forename: Chen-Yong
authors.initials: CY
authors.lastname: Lin
authors.forename: Mesut
authors.initials: M
authors.lastname: Muyan
authors.forename: Shuyuan
authors.initials: S
authors.lastname: Yeh
mesh_terms: D000818:Animals; D002455:Cell Division; D045744:Cell Line, Tumor; D003001:Cloning, Molecular; D047629:Estrogen Receptor beta / Q000502:physiology*; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D051379:Mice; D016133:Polymerase Chain Reaction; D011471:Prostatic Neoplasms / Q000235:genetics* / Q000473:pathology; D034622:RNA Interference; D011960:Receptors, Estrogen / Q000502:physiology; D015398:Signal Transduction; D013737:Testis / Q000502:physiology; D014157:Transcription Factors / Q000502:physiology*; D015533:Transcriptional Activation
chemical_list: C531357:CCDC62 protein, human; D047629:Estrogen Receptor beta; D011960:Receptors, Estrogen; D014157:Transcription Factors