Induction of prostate apoptosis by α1-adrenoceptor antagonists: Mechanistic significance of the quinazoline component

α₁-Adrenoceptor antagonists, have been documented to induce apoptosis and reduce prostate tumor vascularity in benign and malignant prostate cells. The quinazoline based α₁-antagonists, doxazosin and terazosin but not tamsulosin (a sulphonamide derivative) suppress prostate growth without affecting cell proliferation. These quinazoline-mediated apoptotic effects occur via an α₁-adrenoceptor independent mechanism potentially involving activation of the TGF-β signal transduction pathway. This review discusses the current knowledge of the action of quinazoline-derived α₁-adrenoceptor antagonists in the benign and malignant prostate and their potential therapeutic use in the treatment of benign prostatic hyperplasia (BPH) and prostate cancer. Finally, a molecular pathway is proposed for their observed apoptotic function against prostate cells. Increased understanding of the action of these established and clinically accepted agents would provide a basis for the design of safe, effective therapeutic regimens in the treatment of prostatic diseases.