Expression of androgen receptor associated protein 55 (ARA55) in the developing human fetal prostate.
OBJECTIVE
Development and differentiation of the human fetal prostate are androgen dependent and follow a specific pattern of solid bud-ductal morphogenesis, which involves stromal-epithelial interactions. Androgen receptor associated protein 55 (ARA55) an androgen receptor coactivator localized in stromal cells, binds to androgen receptor (AR) and regulates androgen receptor translocation and transcriptional activity. We investigated whether ARA55 has a role in human prostate development.


METHODS
ARA55 expression was examined in 25 human prostates from fetuses at gestational ages 10 to 40 weeks and compared to the expression of 34betaE12 (a basal cell marker), smooth muscle actin, desmin (a smooth muscle marker), vimentin (a mesenchymal marker) and Ki-67 (a proliferation marker) by immunohistochemistry.


RESULTS
Prostatic epithelium appeared as solid epithelial buds from the urogenital sinus. It underwent arborization and ductal differentiation from the center to the periphery. ARA55 was expressed in stromal cells with a zonal pattern, primarily in the peripheral zone surrounding the noncanalized acini. Most cells in solid buds were positive for 34betaE12, while only basal layer cells in the centrally located epithelial ducts stained with 34betaE12. Solid buds also had a higher proliferation index than ducts. In addition, ARA55 expressing stromal cells but not ARA55 negative stromal cells showed smooth muscle differentiation.


CONCLUSIONS
The intimate relationship between ARA55 expressing stromal cells and mitotically active, noncanalized acini suggests that ARA55 has a role in the stromal-epithelial interaction involved in fetal prostate development.
Cai
Guoping
G
Departments of Pathology, New York University School of Medicine, New York Harbor Healthcare System, New York, USA.
Huang
Hongying
H
Shapiro
Ellen
E
Zhou
Holly
H
Yeh
Shuyuan
S
Melamed
Jonathan
J
Greco
M Alba
MA
Lee
Peng
P
D002454:Cell Differentiation / Q000502:physiology; D002455:Cell Division / Q000502:physiology; D003598:Cytoskeletal Proteins / Q000032:analysis*; D004268:DNA-Binding Proteins / Q000032:analysis*; D004848:Epithelium / Q000473:pathology; D005260:Female; D005865:Gestational Age; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D060588:LIM Domain Proteins; D008297:Male; D011247:Pregnancy; D011467:Prostate / Q000196:embryology* / Q000473:pathology; D017154:Stromal Cells / Q000473:pathology
D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D060588:LIM Domain Proteins; C490351:TGFB1I1 protein, human