Bradykinin receptor subtype 1 expression and function in prostate cancer

Kinins exert multiple pathophysiological functions, including vascular permeability and mitogenesis, by activating their cognate receptors, bradykinin subtype 1 receptor (B1R) and bradykinin subtype 2 receptor (B2R), which belong to the superfamily of G protein-coupled receptors. Tissue-specific expression pattern or contribution of the individual kinin receptors to pathological prostate cell growth is not known. We report here the differential expression of B1R and B2R in human benign and malignant prostate specimens. Whereas B2R is ubiquitously expressed, the B1R is detected only in prostatic intraepithelial neoplasia and malignant lesions and not in benign prostate tissues. Using androgen-insensitive prostate cancer PC3 cells, we show that specific stimulation of endogenous B1R promotes cell growth, migration, and invasion. These findings identify B1R as an early marker for pathological growth of the prostate and suggest its potential utility as a drug target effective for the treatment of prostate cancer.