title: Unraveling androgen receptor interactomes by an array-based method: discovery of proto-oncoprotein c-Rel as a negative regulator of androgen receptor.
abstract: The androgen receptor (AR) plays a key role in the development and function of male reproductive organs. Using a high-throughput transcription factor-transcription factor (TF-TF) interaction array method, we captured the AR interactomes in androgen-responsive LNCaP cells. Several known and unknown partners of AR, including AP-2, Pax 3/5 (BSAP), c-Rel, RREB-1, LIII BP, and NPAS2 were identified. We investigated one unreported AR-associated transcription factor, the proto-oncoprotein c-Rel, in detail. C-Rel belongs to the NF-kB/Rel families and is persistently active in a number of diseases, including cancer. The presence of c-Rel transcript, protein, and its in vitro and in vivo association with AR was determined. Co-localization of c-Rel with AR both in cytoplasm and nucleus was confirmed by indirect immunofluorescence analysis. Chromatin immunoprecipitation data indicated that c-Rel, like AR, is a part of the nucleoprotein complex regulating the androgen-responsive prostate-specific antigen (PSA) promoter. Overexpression of c-Rel downregulated the promoter activity of both PSA and GRE4-TATA-Luc plasmids in LNCaP and COS cells. Analysis of AR and c-Rel protein levels indicated that the promoter downregulation was not due to reciprocal decrease in the amounts of AR or c-Rel. In summary, we have identified several new partners of AR by using the TF-TF array method and have provided the first evidence of a functional role for c-Rel in androgen-responsive human prostate cancer cells.
authors.affiliation: Molecular Urology Laboratory, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA. nishit.mukhopadhyay@childrens.harvard.edu <nishit.mukhopadhyay@childrens.harvard.edu>
authors.forename: Nishit K
authors.initials: NK
authors.lastname: Mukhopadhyay
authors.forename: Angeline S
authors.initials: AS
authors.lastname: Ferdinand
authors.forename: Lipi
authors.initials: L
authors.lastname: Mukhopadhyay
authors.forename: Bekir
authors.initials: B
authors.lastname: Cinar
authors.forename: Mohini
authors.initials: M
authors.lastname: Lutchman
authors.forename: Jerome P
authors.initials: JP
authors.lastname: Richie
authors.forename: Michael R
authors.initials: MR
authors.lastname: Freeman
authors.forename: Brian C-S
authors.initials: BC
authors.lastname: Liu
mesh_terms: D001483:Base Sequence; D045744:Cell Line, Tumor; D047369:Chromatin Immunoprecipitation; D017931:DNA Primers / Q000235:genetics; D004268:DNA-Binding Proteins / Q000378:metabolism*; D015536:Down-Regulation; D020573:Genes, rel; D006801:Humans; D008297:Male; D009687:Nuclear Proteins / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D017430:Prostate-Specific Antigen / Q000235:genetics; D011471:Prostatic Neoplasms / Q000235:genetics / Q000378:metabolism; D020569:Proto-Oncogene Proteins c-rel; D011944:Receptors, Androgen / Q000235:genetics* / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014162:Transfection
chemical_list: D017931:DNA Primers; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D020569:Proto-Oncogene Proteins c-rel; C068059:REL protein, human; D011944:Receptors, Androgen; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D017430:Prostate-Specific Antigen