Metastasis-related plasma membrane proteins of human breast cancer cells identified by comparative quantitative mass spectrometry

Research output: Contribution to journalJournal articlepeer-review

The spread of cancer cells from a primary tumor to form metastasis at distant sites is a complex multistep process. The cancer cell proteins and plasma membrane proteins in particular involved in this process are poorly defined, and a study of the very early events of the metastatic process using clinical samples or in vitro assays is not feasible. We have used a unique model system consisting of two isogenic human breast cancer cell lines that are equally tumorigenic in mice; but although one gives rise to metastasis, the other disseminates single cells that remain dormant at distant organs. Membrane purification and comparative quantitative LC-MS/MS proteomics identified 13 membrane proteins that were expressed at higher levels and three that were underexpressed in the metastatic compared with the non-metastatic cell line from a total of 1919 identified protein entries. Among the proteins were ecto-5'-nucleotidase (CD73), NDRG1, integrin beta1, CD44, CD74, and major histocompatibility complex class II proteins. The altered expression levels of proteins identified by LC-MS/MS were validated using flow cytometry, Western blotting, and immunocyto- and immunohistochemistry. Analysis of clinical breast cancer biopsies demonstrated a significant correlation between high ecto-5'-nucleotidase and integrin beta1 expression and poor outcome, measured as tumor spread or distant recurrence within a 10-year follow-up. Further the tissue analysis suggested that NDRG1, HLA-DRalpha, HLA-DRbeta, and CD74 were associated with the ER(-)/PR(-) phenotype represented by the two cell lines. The study demonstrates a quantitative and comparative proteomics strategy to identify clinically relevant key molecules in the early events of metastasis, some of which may prove to be potential targets for cancer therapy.

Original languageEnglish
JournalMolecular and Cellular Proteomics
Volume8
Issue number6
Pages (from-to)1436-49
Number of pages14
ISSN1535-9476
DOIs
Publication statusPublished - Jun 2009

    Research areas

  • Animals, Base Sequence, Blotting, Western, Breast Neoplasms/metabolism, Cell Line, Tumor, Chromatography, Liquid, DNA Primers, Female, Flow Cytometry, Humans, Immunohistochemistry, Membrane Proteins/metabolism, Mice, Neoplasm Metastasis, Neoplasm Proteins/metabolism, Polymerase Chain Reaction, Tandem Mass Spectrometry/methods

ID: 259932608