Mechanism of Azaline B-induced Apoptosis of Ventral Prostate in Rat / 대한비뇨기과학회지

ABSTRACT

PURPOSE: Androgen deprivation triggers a sequence of events that activates apoptotic cell death of the androgen-dependent epithelial cells within the rat ventral prostate, ultimately resulting in the involution of the gland. To investigate the mechanism of azaline B-dependent apoptosis in the rat ventral prostate, the regulation of apoptosis-related genes were examined. MATERIALS AND METHODS: Azaline B was subcutaneously injected in Sprague-Dawley rat. Fas receptor(Fas), Fas ligand(FasL), bcl-2 mRNA, and protein levels were detected by RT-PCR and Western blot. Azaline B-dependent apoptosis was determined by TUNEL and DNA fragmentation assay. Transacting factor of FasL promoter was identified by DNA footprinting and DNA mobility shift assay. RESULTS: The prostate regressed after azaline B treatment in rat, and the involuted ventral prostate regenerated after testosterone pretreatment. Apoptosis of the ventral prostate was detected by TUNEL assay and apoptotic DNA fragmentation assay after azaline B treatment. The levels of Fas and FasL mRNA and protein increased after azaline B treatment. In DNase I footprinting assay with FasL promoter using nuclear extract prepared from control prostate, at least two sites were protected SP-1 binding site at -283bp and prostate-unidentified factor(P-UF) binding site at -247bp. SP-1 binding activity vanished in the nuclear extract prepared from azaline B-treated rats. In the DNA mobility shift assay, SP-1 binding activity decreased after azaline B treatment. Bcl-2 mRNA and protein were downregulated after azaline B treatment. CONCLUSIONS: These results suggest that Fas/FasL system and Bcl-2 are important to azaline B-dependent apoptosis in rat ventral prostate and that SP-1 is related to azaline B-dependent regulation of the FasL gene.