Stromal-epithelial cell interactions and androgen receptor-coregulator recruitment is altered in the tissue microenvironment of prostate cancer.
Tissue recombination experiments show that prostate mesenchyma directs prostate epithelial cell growth and development in an androgen-dependent manner, and that functional differentiation of prostate epithelium requires androgen-driven processes in both epithelia and stroma. The androgen induction of target genes in primary cultures of prostate stromal and epithelial cells was determined using an adenoviral expression system, which employed the MMTV-enhancer driven luciferase reporter as an androgen receptor (AR)-mediated transcription assay. These studies indicate that both cell types contain functional AR. Androgen induction of luciferase reporter activity is 3-fold in stromal cells compared with 10-fold in epithelial cells. AR-mediated transcription activity in stroma cells was enhanced by coculture with epithelial cells or epithelial cell-conditioned media. The elevated AR-mediated transcription activity in stromal cells that were exposed to epithelial factors correlated with increased recruitment of coactivators to the AR transcriptional complex. Epithelial cells facilitated interactions of AR with SRC-1 in an androgen-dependent manner. However, AR-mediated transcriptional activity in stromal cells isolated from prostate cancer was reduced compared with stromal cells isolated from benign prostate and continued to be reduced when cocultured with tumor-derived prostate epithelial cells. The occupancy of AR and coregulators on target genes showed that androgen-bound AR in prostate cancer stromal cells was associated with the corepressor silencing mediator for retinoid and thyroid hormone receptor. Thus, the ability of epithelial cells to modulate coregulator recruitment to the AR transcriptional complex on androgen-responsive genes seems altered in the stromal microenvironment of prostate cancer.
Cano
Patricia
P
Department of Urologic Oncology, Roswell Park Cancer Institute, Buffalo, New York 14213, and Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
Godoy
Alejandro
A
Escamilla
Rosalba
R
Dhir
Rajiv
R
Onate
Sergio A
SA
D002450:Cell Communication / Q000502:physiology*; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008297:Male; D009687:Nuclear Proteins / Q000378:metabolism*; D056971:Nuclear Receptor Co-Repressor 1; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000473:pathology*; D011944:Receptors, Androgen / Q000378:metabolism*; D012097:Repressor Proteins / Q000378:metabolism*; D017154:Stromal Cells / Q000378:metabolism / Q000473:pathology; D014158:Transcription, Genetic
C539127:NCOR1 protein, human; D009687:Nuclear Proteins; D056971:Nuclear Receptor Co-Repressor 1; D011944:Receptors, Androgen; D012097:Repressor Proteins