Progression of Osteosarcoma from a Non-Metastatic to a Metastatic Phenotype Is Causally Associated with Activation of an Autocrine and Paracrine uPA Axis
Open Access
- 28 August 2015
- journal article
- research article
- Published by Public Library of Science (PLoS) in PLOS ONE
- Vol. 10 (8), e0133592
- https://doi.org/10.1371/journal.pone.0133592
Abstract
Pulmonary metastasis is the major untreatable complication of osteosarcoma (OS) resulting in 10–20% long-term survival. The factors and pathways regulating these processes remain unclear, yet their identification is crucial in order to find new therapeutic targets. In this study we used a multi-omics approach to identify molecules in metastatic and non-metastatic OS cells that may contribute to OS metastasis, followed by validation in vitro and in vivo. We found elevated levels of the urokinase plasminogen activator (uPA) and of the uPA receptor (uPAR) exclusively in metastatic OS cells. uPA was secreted in soluble form and as part of the protein cargo of OS-secreted extracellular vesicles, including exosomes. In addition, in the tumour microenvironment, uPA was expressed and secreted by bone marrow cells (BMC), and OS- and BMC-derived uPA significantly and specifically stimulated migration of metastatic OS cells via uPA-dependent signaling pathways. Silencing of uPAR in metastatic OS cells abrogated the migratory response to uPA in vitro and decreased metastasis in vivo. Finally, a novel small-molecule inhibitor of uPA significantly (P = 0.0004) inhibited metastasis in an orthotopic mouse model of OS. Thus, we show for the first time that malignant conversion of OS cells to a metastatic phenotype is defined by activation of the uPA/uPAR axis in both an autocrine and paracrine fashion. Furthermore, metastasis is driven by changes in OS cells as well as in the microenvironment. Finally, our data show that pharmacological inhibition of the uPA/uPAR axis with a novel small-molecule inhibitor can prevent the emergence of metastatic foci.Keywords
This publication has 54 references indexed in Scilit:
- The multifaceted exosome: Biogenesis, role in normal and aberrant cellular function, and frontiers for pharmacological and biomarker opportunitiesBiochemical Pharmacology, 2012
- Melanoma exosomes educate bone marrow progenitor cells toward a pro-metastatic phenotype through METNature Medicine, 2012
- miRNA Signatures Associate with Pathogenesis and Progression of OsteosarcomaCancer Research, 2012
- Expression of PTRF in PC-3 Cells Modulates Cholesterol Dynamics and the Actin Cytoskeleton Impacting Secretion PathwaysMolecular & Cellular Proteomics, 2012
- ImmunoRatio: a publicly available web application for quantitative image analysis of estrogen receptor (ER), progesterone receptor (PR), and Ki-67Breast Cancer Research, 2010
- Molecular and pathological signatures of epithelial–mesenchymal transitions at the cancer invasion frontHistochemistry and Cell Biology, 2008
- Pre-EMTing metastasis? Recapitulation of morphogenetic processes in cancerClinical & Experimental Metastasis, 2007
- Illuminating the metastatic processNature Reviews Cancer, 2007
- An Orthotopic Model of Human Osteosarcoma Growth and Spontaneous Pulmonary MetastasisClinical & Experimental Metastasis, 2005
- A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye bindingAnalytical Biochemistry, 1976