The alpha-receptor for platelet-derived growth factor confers bone-metastatic potential to prostate cancer cells by ligand- and dimerization-independent mechanisms.

Abstract

Prostate adenocarcinoma is the second leading cause of cancer death among men, due primarily to the fact that the majority of prostate cancers will eventually spread to the skeleton. Metastatic dissemination requires a complex series of coordinated events that result in cells that escape from the primary tumor into the circulation and eventually colonize a distant organ. The ability of these cells to evolve into macroscopic metastases depends strongly on their compatibility with, and ability to utilize, this new microenvironment. We previously showed that bone-metastatic prostate cancer cells exposed to human bone marrow respond by activation of cell survival pathways, such as phosphoinositide 3-kinase/Akt, and that these events are mediated by the alpha-receptor for platelet-derived growth factor (PDGFRalpha). Our studies and others have shown that PDGFRalpha may be activated by mechanisms independent of PDGF ligand binding. Here, we provide conclusive evidence that soluble components of human bone marrow can activate PDGFRalpha through a mechanism that does not require the canonical binding of PDGF ligand(s) to the receptor. In particular, we found that dimerization of PDGFRalpha monomers is not induced by human bone marrow, but this does not prevent receptor phosphorylation and downstream signaling from occurring. To establish the relevance of this phenomenon in vivo, we used a PDGFRalpha mutant lacking the extracellular ligand-binding domain. Our studies show that this truncated PDGFRalpha is able to restore bone-metastatic potential of prostate cancer cells as effectively as the full-length form of the receptor.

• Authors: Mike R Russell, Qingxin Liu, Hetian Lei, Andrius Kazlauskas, Alessandro Fatatis
• Journal: Cancer research (Cancer Res) Vol. 70 Issue 10 Pg. 4195-203 (May 15 2010) ISSN: 1538-7445 [Electronic] United States
• PMID: 20442296 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: (c)2010 AACR.

Chemical References

• Ligands
• Receptor, Platelet-Derived Growth Factor alpha

Topics

• Adolescent
• Adult
• Animals
• Blotting, Western
• Bone Marrow (metabolism, pathology)
• Bone Neoplasms (metabolism, secondary)
• Dimerization
• Humans
• Ligands
• Male
• Mice
• Mice, Nude
• Middle Aged
• Phosphorylation
• Prostatic Neoplasms (metabolism, pathology)
• Receptor, Platelet-Derived Growth Factor alpha (metabolism)
• Tumor Cells, Cultured
• Young Adult