Identification of breast cancer peptide epitopes presented by HLA-A*0201.

Hawkins OE, Vangundy RS, Eckerd AM, Bardet W, Buchli R, Weidanz JA, Hildebrand WH
J Proteome Res. 2008 7 (4): 1445-57

PMID: 18345606 · DOI:10.1021/pr700761w

Cellular immune mechanisms detect and destroy cancerous and infected cells via the human leukocyte antigen (HLA) class I molecules that present peptides of intracellular origin on the surface of all nucleated cells. The identification of novel, tumor-specific epitopes is a critical step in the development of immunotherapeutics for breast cancer. To directly identify peptide epitopes unique to cancerous cells, secreted human class I HLA molecules (sHLA) were constructed by deletion of the transmembrane and cytoplasmic domain of HLA A*0201. The resulting sHLA-A*0201 was transferred and expressed in breast cancer cell lines MCF-7, MDA-MB-231, and BT-20 as well as in the immortal, nontumorigenic cell line MCF10A. Stable transfectants were seeded into bioreactors for production of > 25 mg of sHLA-A*0201. Peptides eluted from affinity purified sHLA were analyzed by mass spectroscopy. Comparative analysis of HLA-A*0201 peptides revealed 5 previously uncharacterized epitopes uniquely presented on breast cancer cells. These peptides were derived from intracellular proteins with either well-defined or putative roles in breast cancer development and progression: Cyclin Dependent Kinase 2 (Cdk2), Ornithine Decarboxylase (ODC1), Kinetochore Associated 2 (KNTC2 or HEC1), Macrophage Migration Inhibitory Factor (MIF), and Exosome Component 6 (EXOSC6). Cellular recognition of the MIF, KNTC2, EXOSC6, and Cdk2 peptides by circulating CD8+ cells was demonstrated by tetramer staining and IFN-gamma ELISPOT. The identification and characterization of peptides unique to the class I of breast cancer cells provide putative targets for the development of immune diagnostic tools and therapeutics.

MeSH Terms (20)

Amino Acid Sequence Breast Neoplasms CD8-Positive T-Lymphocytes Cell Line, Tumor Chromatography, High Pressure Liquid Cyclin-Dependent Kinase 2 Cytoskeletal Proteins Epitopes, T-Lymphocyte Exoribonucleases Female HLA-A2 Antigen HLA-A Antigens Humans Interferon-gamma Intramolecular Oxidoreductases Leukocytes, Mononuclear Macrophage Migration-Inhibitory Factors Mass Spectrometry Nuclear Proteins Ornithine Decarboxylase

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