HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: M800443-MCP200v1 8/6/1192    most recent Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Glossary Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Jansen, F. H. Articles by Jenster, G. Search for Related Content PubMed PubMed Citation Articles by Jansen, F. H. Articles by Jenster, G. Social Bookmarking                      What's this?

Molecular & Cellular Proteomics 8:1192-1205, 2009.
© 2009 by The American Society for Biochemistry and Molecular Biology, Inc.

---

Research

Exosomal Secretion of Cytoplasmic Prostate Cancer Xenograft-derived Proteins^*,

Flip H. Jansen, Jeroen Krijgsveld, Angelique van Rijswijk, Gert-Jan van den Bemd, Mirella S. van den Berg, Wytske M. van Weerden, Rob Willemsen^¶, Lennard J. Dekker^||, Theo M. Luider^|| and Guido Jenster^,**

From the Departments of Urology,
¶Clinical Genetics, and
||Neurology Erasmus Medical Center, 3000 CA Rotterdam, The Netherlands and
Department of Biomolecular Mass Spectrometry, Utrecht University, 3584 CA Utrecht, The Netherlands

Novel markers for prostate cancer (PCa) are needed because current established markers such as prostate-specific antigen lack diagnostic specificity and prognostic value. Proteomics analysis of serum from mice grafted with human PCa xenografts resulted in the identification of 44 tumor-derived proteins. Besides secreted proteins we identified several cytoplasmic proteins, among which were most subunits of the proteasome. Native gel electrophoresis and sandwich ELISA showed that these subunits are present as proteasome complexes in the serum from xenograft-bearing mice. We hypothesized that the presence of proteasome subunits and other cytoplasmic proteins in serum of xenografted mice could be explained by the secretion of small vesicles by cancer cells, so-called exosomes. Therefore, mass spectrometry and Western blotting analyses of the protein content of exosomes isolated from PCa cell lines was performed. This resulted in the identification of mainly cytoplasmic proteins of which several had previously been identified in the serum of xenografted mice, including proteasome subunits. The isolated exosomes also contained RNA, including the gene fusion TMPRSS2-ERG product. These observations suggest that although their function is not clearly defined cancer-derived exosomes offer possibilities for the identification of novel biomarkers for PCa.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?