Mechanism of Castration-induced Apoptosis of Ventral Prostate in Rat / 대한내분비학회지

ABSTRACT

BACKGROUNDS Castration-induced androgen deprivation triggers a sequence of events, which activates apoptotic cell death of the androgen-dependent epithelial cells within the rat ventral prostate. To investigate the mechanism of castration-dependent apoptosis in the rat ventral prostate, the regulation of apoptosis-related genes was been investigated. METHODS: Azaline B was subcutaneously injected into Sprague-Dawley rat. The Fas receptor (Fas), Fas ligand (FasL) and bcl-2 mRNA, as well as the protein levels were detected by RT-PCR and Western blot analyses. Azaline B-dependent apoptosis was determined using TUNEL and a DNA fragmentation assay. The transacting factor of the FasL promoter was identified by DNA footprinting and a DNA mobility shift assay. RESULTS: The rat prostate was regressed after castration, with and the involuted ventral prostate regenerated by testosterone pretreatment, but not by that with FSH. Apoptosis of the ventral prostate was detected, after castration, using toluidine blue staining, a TUNEL assay and an apoptotic DNA fragmentation assay. The levels of Fas, FasL mRNA and protein were increased after castration. In the DNase I footprinting assay, using the FasL promoter and a nuclear extract prepared from a control prostate, at least two sites were protected the SP-1 binding site at -283 bp and the prostate-unidentified factor(P-UF) binding site at -247 bp. The SP-1 binding activity vanished in the nuclear extract prepared from castrated rats. In the DNA mobility shift assay, the SP-1 binding activity was slightly decreased after castration. Both the Bcl-2 mRNA and Bcl-2 protein were downregulated after castration. CONCLUSION: These results suggest that the Fas/FasL system and Bcl-2 may be important to castrationdependent apoptosis in the rat ventral prostate, with SP-1 related to the castration-dependent regulation of the FasL gene