Doxazosin Attenuates Development of Testosterone Propionate-induced Prostate Growth by regulating TGF-β/Smad Signaling Pathway, Prostate-specific Antigen Expression and Reversing Epithelial-Mesenchymal Transition in Mice and Stroma Cells

Background Finasteride and doxazosin are used for the treatment of benign prostatic hyperplasia (BPH) and lower urinary tract symptoms (LUTS). Epithelial–mesenchymal transition (EMT) and TGF-β/Smad signaling pathway play an important role in BPH, little is known about the growth inhibition and anti-fibrosis effects of doxazosin on the regulation of EMT and morphology in the prostate. Objectives The present study examined the effects of doxazosin on testosterone propionate (TP)-induced prostate growth in vivo and in vitro and its impact on the EMT and TGF-β/Smad signaling pathway. Methods Mice were treated with TP. Doxazosin (5 or 10 mg/kg) and finasteride (10 mg/kg) were administered orally for 28 days in TP-induced mice. The prostate index (prostate/body weight ratio), morphological characteristics and the protein expression of the prostate were examined. We further examined the effects of doxazosin and finasteride on the EMT and TGF-β/Smad signaling pathway in mice and in human prostate stroma cell (WPMY-1). The protein expressions of TGF-β1, TGFBR2, p-Smad2/3, N-cadherin, vimentin, fibronectin and α-SMA, E-cadherin and prostate specific antigen (PSA) were determined after treatment by western blot. Results The prostate wet weight, prostate index decreased after treatment. Doxazosin (5 or 10 mg/kg), finasteride (10 mg/kg) or a combination treatment (doxazosin 10 mg/kg + finasteride 10 mg/kg) were shown to reverse the pathological and morphological characteristics of the prostate. Doxazosin and finasteride inhibited TP-induced prostate growth, EMT, and the TGF-β/Smad signaling pathway by downregulating the expression of TGF-β1, TGFBR2, p-Smad2/3, N-cadherin, vimentin, fibronectin and α-SMA, whereas expression of E-cadherin was increased after treatment with either doxazosin or finasteride. Doxazosin (1-50 μM) inhibited normal human prostate stroma cell growth (WPMY-1) after 48 h with or without testosterone treatment. Doxazosin also regulated the EMT and proteins related to the TGF-β/Smad signaling pathway in WPMY-1 cells after 24 h. Additionally, doxazosin decreased protein expression of the PSA both in vivo and in vitro. Conclusion This study demonstrated that doxazosin inhibits prostate growth by regulating the EMT and TGF-β/Smad signaling pathways in the prostate. This finding suggests that doxazosin has potential as a new signaling pathway for the treatment of BPH.