Abstract
Locally produced nonpituitary growth hormone (npGH) promotes DNA damage accumulation and epithelial-mesenchymal transition (EMT) in aging human colon epithelium. GH receptor (GHR) and npGH are expressed in normal human prostate and benign prostatic hyperplasia (BPH) prevalence increases with age. We hypothesized that local prostate GH action may promote EMT and contribute to BPH pathogenesis. We show here that the number of patients expressing npGH increases >10-fold after age 60, concordant with increased γH2AX, a marker of DNA damage, and EMT activation. GH-treated human primary prostate epithelial cells, normal prostate cells, and primary cell cultures derived from resected BPH specimens exhibited enhanced DNA damage and activated EMT, with induced TWIST2 and suppressed E-cadherin, as well as increased Ki67, cell motility, and proliferation. In mice, prostate tissue adjacent to allografted GH-expressing fibroblasts showed increased γH2AX, TWIST2, and Ki67 compared to controls, along with morphological changes consistent with BPH. While GH and GH-induced IGF-1 both activated EMT, GH triggered DNA damage independent of IGF-1. These results elucidate a novel role for local npGH in aging prostate tissue, whereby npGH increases DNA damage and promotes EMT to enable a microenvironment favoring BPH development. Prostate GHR signaling may be an attractive therapeutic target for BPH.
Authors
Masaki Ryuzaki, Svetlana Zonis, Neil A. Bhowmick, Sandrine Billet, Saravana Kumar Kailasam Mani, Stephen J. Freedland, Hyung L. Kim, Vera Chesnokova, Shlomo Melmed
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