title: The human antibody fragment DIATHIS1 specific for CEACAM1 enhances natural killer cell cytotoxicity against melanoma cell lines in vitro.
abstract: Several lines of evidence show that de novo expression of carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) is strongly associated with reduced disease-free survival of patients affected by metastatic melanoma. Previously published investigations report that homophilic interactions between CEACAM1 expressed on natural killer (NK) cells and tumors inhibit the NK cell-mediated killing independently of major histocompatibility complex class I recognition. This biological property can be physiologically relevant in metastatic melanoma because of the increased CEACAM1 expression observed on NK cells from some patients. Moreover, this inhibitory mechanism in many cases might hinder the efficacy of immunotherapeutic treatments of CEACAM1 malignancies because of tumor evasion by activated effector cells. In the present study, we designed an in vitro experimental model showing that the human single-chain variable fragment (scFv) DIATHIS1 specific for CEACAM1 is able to enhance the lytic machinery of NK cells against CEACAM1 melanoma cells. The coincubation of the scFv DIATHIS1 with CEACAM1 melanoma cells and NK-92 cell line significantly increases the cell-mediated cytotoxicity. Moreover, pretreatment of melanoma cells with scFv DIATHIS1 promotes the activation and the degranulation capacity of in vitro-expanded NK cells from healthy donors. It is interesting to note that the melanoma cell line MelC and the primary melanoma cells STA that respond better to DIATHIS1 treatment, express higher relative levels of CEACAM1-3L and CEACAM1-3S splice variants isoforms compared with Mel501 cells that are less responsive to DIATHIS1-induced NK cell-mediated cytotoxicity. Taken together, our results suggest that the fully human antibody fragment DIATHIS1 originated by biopanning approach from a phage antibody library may represent a relevant biotechnological platform to design and develop completely human antimelanoma therapeutics of biological origin.
authors.affiliation: *Department of Therapeutic Research and Medicines Evaluation, Istituto Superiore di Sanità ‡Department of Molecular Medicine, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome †Diatheva S.R.L., Fano §Department of Biomolecular Science, University of Urbino "Carlo Bo," Urbino, PU, Italy.
authors.forename: Maria L
authors.initials: ML
authors.lastname: Dupuis
authors.forename: Valentina
authors.initials: V
authors.lastname: Fiori
authors.forename: Alessandra
authors.initials: A
authors.lastname: Soriani
authors.forename: Biancamaria
authors.initials: B
authors.lastname: Ricci
authors.forename: Sabrina
authors.initials: S
authors.lastname: Dominici
authors.forename: Diego
authors.initials: D
authors.lastname: Moricoli
authors.forename: Alessandro
authors.initials: A
authors.lastname: Ascione
authors.forename: Angela
authors.initials: A
authors.lastname: Santoni
authors.forename: Mauro
authors.initials: M
authors.lastname: Magnani
authors.forename: Maurizio
authors.initials: M
authors.lastname: Cianfriglia
mesh_terms: D000920:Antibody-Dependent Cell Cytotoxicity; D015703:Antigens, CD / Q000276:immunology*; D015815:Cell Adhesion Molecules / Q000276:immunology*; D045744:Cell Line, Tumor; D006801:Humans; D007167:Immunotherapy; D007694:Killer Cells, Natural / Q000276:immunology; D008545:Melanoma / Q000276:immunology / Q000628:therapy; D057127:Single-Chain Antibodies / Q000276:immunology / Q000627:therapeutic use
chemical_list: D015703:Antigens, CD; C069847:CD66 antigens; D015815:Cell Adhesion Molecules; D057127:Single-Chain Antibodies