Exosomal Release of L-Plastin by Breast Cancer Cells Facilitates Metastatic Bone Osteolysis.

Abstract

Bone metastasis from breast and prostate carcinomas is facilitated by activation of bone-resorbing osteoclasts. Using proteomics approaches, we have identified peroxiredoxin-4 (PRDX4) as a cancer-secreted mediator of osteoclastogenesis. We now report characterization of L-plastin in the conditioned media (CM) of MDA-MB-231 human breast cancer cells using immunoblotting and mass spectrometry. The osteoclastogenic potential of MDA-MB-231 CM with siRNA-silenced L-plastin was significantly reduced. L-plastin was detected in cancer-derived exosomes, and inhibition of exosomal release significantly decreased the osteoclastogenic capacity of MDA-MB-231 CM. When added to osteoclast precursors primed with RANKL for 2 days, recombinant L-plastin induced calcium/NFATc1-mediated osteoclastogenesis to the levels similar to continuous treatment with RANKL. Using shRNA, we generated MDA-MB-231 cells lacking L-plastin, PRDX4, or both and injected these cell populations intratibially in CD-1 immunodeficient mice. Micro-CT and histomorphometric analysis demonstrated a complete loss of osteolysis when MDA-MB-231 cells lacking both L-plastin and PRDX4 were injected. A meta-analysis established an increase in L-plastin and PRDX4 mRNA expression in numerous human cancers, including breast and prostate carcinomas. This study demonstrates that secreted L-plastin and PRDX4 mediate osteoclast activation by human breast cancer cells.

• Authors: Kerstin Tiedemann, Gulzhakhan Sadvakassova, Nicholas Mikolajewicz, Michal Juhas, Zarina Sabirova, Sébastien Tabariès, Jan Gettemans, Peter M Siegel, Svetlana V Komarova
• Journal: Translational oncology (Transl Oncol) Vol. 12 Issue 3 Pg. 462-474 (Mar 2019) ISSN: 1936-5233 [Print] United States
• PMID: 30583289 (Publication Type: Journal Article)
• Copyright: Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.