Unraveling androgen receptor interactomes by an array-based method: discovery of proto-oncoprotein c-Rel as a negative regulator of androgen receptor.
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.
Mukhopadhyay
Nishit K
NK
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>
Ferdinand
Angeline S
AS
Mukhopadhyay
Lipi
L
Cinar
Bekir
B
Lutchman
Mohini
M
Richie
Jerome P
JP
Freeman
Michael R
MR
Liu
Brian C-S
BC
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
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