Recently, a new experimental stromal hyperplasia animal model corresponding to clinical benign prostatic hyperplasia (BPH) was established. The main objective of this study was to elucidate the roles of the intermediate-conductance Ca2+-activated K+ channel (KCa3.1) in the implanted urogenital sinus (UGS) of stromal hyperplasia BPH model rats. Using DNA microarray, real-time PCR, Western blot, and/or immunohistochemical analyses, we identified the expression of KCa3.1 and its transcriptional regulators in implanted UGS of BPH model rats and prostate needle-biopsy samples and surgical prostate specimens of BPH patients. We also examined the in vivo effects of a KCa3.1 blocker, TRAM-34, on the proliferation index of implanted UGS by measurement of UGS weights and PCNA immunostaining. KCa3.1 genes and proteins were highly expressed in implanted UGS rather than in the normal host prostate. In implanted UGS, the gene expressions of two transcriptional regulators of KCa3.1, a repressor element 1-silencing transcription factor (REST) and c-Jun, were significantly down- and up-regulated, and the regulations were negatively or positively correlated with KCa3.1 expression, respectively. Positive signals of KCa3.1 proteins were detected exclusively in stromal cells, whereas they were scarcely immunolocalized to basal cells of the epithelium in implanted UGS. In vivo treatment with TRAM-34 significantly suppressed the increase in implanted UGS weights compared with the decrease in stromal cell components. Moreover, significant levels of KCa3.1 expression were observed in human BPH samples. KCa3.1 blockers may be a novel treatment option for patients suffering from BPH.
- Received April 7, 2011.
- Revision received May 19, 2011.
- Accepted May 19, 2011.
- The American Society for Pharmacology and Experimental Therapeutics