The α1-adrenoceptor-mediated human hyperplastic prostate cells proliferation is impaired by EGF receptor inhibition.

Benign prostatic hyperplasia (BPH) is an aging-related and progressive disease linked to an up-regulation of α-adrenoceptors. The participation of EGF receptors (EGFR) in the GPCRs' signalosome has been described but so far data about the contribution of these receptors to prostatic stromal hyperplasia are scanty. We isolated and cultured vimentin-positive prostate stromal cells obtained from BPH patients. According to intracellular Ca measurements, cell proliferation and Western blotting assays, these cultured hyperplastic stromal cells express functional αadrenoceptors and EGFR, and proliferate in response to the αadrenoceptor agonist phenylephrine. Interestingly, in these cells the inhibition of EGFR signaling with GM6001, CRM197, AG1478 or PD98059 was associated with full blockage of α-adrenoceptor-mediated cell proliferation, while cell treatment with each inhibitor alone did not alter basal cell growth. Moreover, the co-incubation of AG1478 (EGFR inhibitor) with αα-adrenoceptor antagonists showed no additive inhibitory effect. These findings highlight a putative role of EGFR signaling to α-adrenoceptor-mediated human prostate hyperplasia, suggesting that the inhibition of this transactivation cascade could be useful to reduce BPH progression.