Identification of new accessible tumor antigens in human colon cancer by ex vivo protein biotinylation and comparative mass spectrometry analysis

Authors

  • Paolo Conrotto,

    1. Department of Chemistry and Applied Biosciences, ETH Zurich, Wolfang-Pauli-Strasse 10, 8093 Zurich, Switzerland
    Search for more papers by this author
  • Christoph Roesli,

    1. Department of Chemistry and Applied Biosciences, ETH Zurich, Wolfang-Pauli-Strasse 10, 8093 Zurich, Switzerland
    Search for more papers by this author
  • Jascha Rybak,

    1. Department of Chemistry and Applied Biosciences, ETH Zurich, Wolfang-Pauli-Strasse 10, 8093 Zurich, Switzerland
    Search for more papers by this author
  • Philippe Kischel,

    1. Metastasis Research Laboratory, Center of Experimental Cancer Research, University of Liège, Tour de Pathologie-1, 4000 Liege, Belgium
    Search for more papers by this author
  • David Waltregny,

    1. Metastasis Research Laboratory, Center of Experimental Cancer Research, University of Liège, Tour de Pathologie-1, 4000 Liege, Belgium
    Search for more papers by this author
  • Dario Neri,

    Corresponding author
    1. Department of Chemistry and Applied Biosciences, ETH Zurich, Wolfang-Pauli-Strasse 10, 8093 Zurich, Switzerland
    • Department of Chemistry and Applied Biosciences, ETHZ, Wolfang-Pauli-Strasse 10, 8093 Zurich, Switzerland
    Search for more papers by this author
    • Fax: + 41-446-331-358.

  • Vincent Castronovo

    1. Metastasis Research Laboratory, Center of Experimental Cancer Research, University of Liège, Tour de Pathologie-1, 4000 Liege, Belgium
    Search for more papers by this author

  • Conflict of Interest: All the authors declare that they have not any conflict of interest regarding the results and experimental approaches described in the present manuscript.

Abstract

One of the most promising new strategies for the development of efficacious cancer therapies relies on the targeted delivery of biopharmaceutical to the tumor environment by the use of selective and specific antibodies. The identification of accessible perivascular proteins selectively overexpressed in cancer tissue may facilitate the development of antibody-based biopharmaceutical administration. This approach is potentially highly selective and specific, combining the presence of tumor biomarkers readily accessible from the blood vessels and the high rate of angiogenesis characteristic of cancer tissues. We performed ex vivo perfusions of surgically resected human colon cancer using a reactive ester derivative of biotin, thus achieving a selective covalent modification of accessible proteins in vascular structures and stroma. After extraction and purification, biotinylated proteins were digested and the resulting peptides submitted to a comparative mass spectrometry-based proteomic analysis, revealing quantitative differences between normal and cancer colon. Sixty-seven of the total 367 proteins identified were found to be preferentially expressed at the tumor site. We generated human monoclonal antibodies against 2 potential tumor targets, NGAL and GW112, and we proved their selective expression in cancer colon and not or barely in healthy tissues. This article presents the first proteomic analysis of human colorectal cancer structures readily accessible from the tumor vasculature, revealing the overexpression of novel tumor antigens which may serve as selective targets for antibody-based imaging and therapeutic biomolecular strategies. © 2008 Wiley-Liss, Inc.

Ancillary