1. ¹Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA 19102, USA
2. ²Department of Pathology, Drexel University College of Medicine, Philadelphia, PA 19102, USA

Correspondence: A Fatatis, Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N. 15th Street, New College Building MS488, Philadelphia, PA 19102, USA. E-mail: af39@drexel.edu

Received 24 February 2005; Revised 22 April 2005; Accepted 22 April 2005; Published online 20 June 2005.

Abstract

Prostate adenocarcinoma metastasizes to the skeleton more frequently than any other organ. An underlying cause of this phenomenon may be the ability of bone-produced factors to specifically select disseminated prostate cancer cells that are susceptible to their trophic effects. Platelet-derived growth factor (PDGF), a potent mitogen for both normal and tumor cells, is produced in several tissues including bone, where it is synthesized by both osteoblasts and osteoclasts. Here, we show that PDGF causes a significantly stronger activation of the Akt/PKB survival pathway in bone-metastatic prostate cancer cells compared to nonmetastatic cells. Normal prostate epithelial cells and DU-145 prostate cells, originally derived from a brain metastasis, are not responsive to PDGF. In contrast, epidermal growth factor stimulates Akt to the same extent in all prostate cells tested. This difference in PDGF responsiveness depends on the higher expression of -PDGFR in bone-metastatic compared to nonmetastatic prostate cells and the lack of -PDGFR expression in normal and metastatic prostate cells derived from tissues other than bone. Thus, -PDGFR expression might identify prostate cancer cells with the highest propensity to metastasize to the skeleton.