title: The proteasome immunosubunits, PA28 and ER-aminopeptidase 1 protect melanoma cells from efficient MART-126-35 -specific T-cell recognition.
abstract: The immunodominant MART-1(26(27)-35) epitope, liberated from the differentiation antigen melanoma antigen recognized by T cells/melanoma antigen A (MART-1/Melan-A), has been frequently targeted in melanoma immunotherapy, but with limited clinical success. Previous studies suggested that this is in part due to an insufficient peptide supply and epitope presentation, since proteasomes containing the immunosubunits β5i/LMP7 (LMP, low molecular weight protein) or β1i/LMP2 and β5i/LMP7 interfere with MART-1(26-35) epitope generation in tumor cells. Here, we demonstrate that in addition the IFN-γ-inducible proteasome subunit β2i/MECL-1 (multicatalytic endopeptidase complex-like 1), proteasome activator 28 (PA28), and ER-resident aminopeptidase 1 (ERAP1) impair MART-1(26-35) epitope generation. β2i/MECL-1 and PA28 negatively affect C- and N-terminal cleavage and therefore epitope liberation from the proteasome, whereas ERAP1 destroys the MART-1(26-35) epitope by overtrimming activity. Constitutive expression of PA28 and ERAP1 in melanoma cells indicate that both interfere with MART-1(26-35) epitope generation even in the absence of IFN-γ. In summary, our results provide first evidence that activities of different antigen-processing components contribute to an inefficient MART-1(26-35) epitope presentation, suggesting the tumor cell's proteolytic machinery might have an important impact on the outcome of epitope-specific immunotherapies.
authors.affiliation: Institut für Biochemie, Charité-Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Keller
authors.affiliation: Institut für Biochemie, Charité-Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Ebstein
authors.affiliation: Institut für Biochemie, Charité-Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Elke
authors.initials: E
authors.lastname: Bürger
authors.affiliation: Institut für Biochemie, Charité-Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Kathrin
authors.initials: K
authors.lastname: Textoris-Taube
authors.affiliation: Institut für Molekulare und Klinische Immunologie, Medizinische Fakultät, Otto-von-Guericke-Universität Magdeburg, Magdeburg, Germany.
authors.forename: Xenia
authors.initials: X
authors.lastname: Gorny
authors.affiliation: Institut für Biochemie, Charité-Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Urban
authors.affiliation: Klinik für Dermatologie, Universitätsklinikum Essen, Essen and German Cancer Consortium (DKTK), Universität Duisburg-Essen, Essen, Germany.
authors.forename: Fang
authors.initials: F
authors.lastname: Zhao
authors.affiliation: Klinik für Dermatologie, Universitätsklinikum Essen, Essen and German Cancer Consortium (DKTK), Universität Duisburg-Essen, Essen, Germany.
authors.forename: Tanja
authors.initials: T
authors.lastname: Dannenberg
authors.affiliation: Klinik für Dermatologie, Universitätsklinikum Essen, Essen and German Cancer Consortium (DKTK), Universität Duisburg-Essen, Essen, Germany.
authors.forename: Antje
authors.initials: A
authors.lastname: Sucker
authors.affiliation: Institut für Biochemie, Charité-Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Christin
authors.initials: C
authors.lastname: Keller
authors.affiliation: INSERM, Unité 1151, Hôpital Necker, Paris, France.
authors.forename: Loredana
authors.initials: L
authors.lastname: Saveanu
authors.affiliation: Institut für Biochemie, Charité-Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Elke
authors.initials: E
authors.lastname: Krüger
authors.affiliation: Institut für Anatomie, Medizinische Fakultät, Otto-von-Guericke-Universität Magdeburg, Magdeburg, Germany.
authors.forename: Hermann-Josef
authors.initials: HJ
authors.lastname: Rothkötter
authors.affiliation: Institut für Biochemie, Charité-Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Burkhardt
authors.initials: B
authors.lastname: Dahlmann
authors.affiliation: Institut für Biochemie, Charité-Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Petra
authors.initials: P
authors.lastname: Henklein
authors.affiliation: Institut für Biochemie, Charité-Universitätsmedizin Berlin, Berlin, Germany.|DZHK (German Centre for Cardiovascular Research), Institut für Biochemie, Charité-Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Antje
authors.initials: A
authors.lastname: Voigt
authors.affiliation: Institut für Biochemie, Charité-Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Kuckelkorn
authors.affiliation: Klinik für Dermatologie, Universitätsklinikum Essen, Essen and German Cancer Consortium (DKTK), Universität Duisburg-Essen, Essen, Germany.
authors.forename: Annette
authors.initials: A
authors.lastname: Paschen
authors.affiliation: Institut für Biochemie, Charité-Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Peter-Michael
authors.initials: PM
authors.lastname: Kloetzel
authors.affiliation: Institut für Biochemie, Charité-Universitätsmedizin Berlin, Berlin, Germany.|Institut für Molekulare und Klinische Immunologie, Medizinische Fakultät, Otto-von-Guericke-Universität Magdeburg, Magdeburg, Germany.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Seifert
mesh_terms: D000626:Aminopeptidases / Q000502:physiology*; D045744:Cell Line, Tumor; D003546:Cysteine Endopeptidases / Q000502:physiology; D000939:Epitopes / Q000276:immunology*; D006801:Humans; D008545:Melanoma / Q000276:immunology*; D015778:Minor Histocompatibility Antigens; D009124:Muscle Proteins / Q000502:physiology*; D009363:Neoplasm Proteins / Q000276:immunology*; D046988:Proteasome Endopeptidase Complex / Q000502:physiology*; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000939:Epitopes; C105787:MART-1-Melan-A(27-35) epitope; D015778:Minor Histocompatibility Antigens; D009124:Muscle Proteins; D009363:Neoplasm Proteins; C085047:PSME1 protein, human; C071313:LMP-2 protein; D000626:Aminopeptidases; C464841:ERAP1 protein, human; D003546:Cysteine Endopeptidases; C077436:LMP7 protein; D046988:Proteasome Endopeptidase Complex
keywords: Antigen processing; Cellular cytotoxicity; ER-aminopeptidase; Melanoma; Melanoma antigen recognized by T cells/melanoma antigen A; PA28; Proteasome subunit