title: Treatment of colon and breast carcinoma cells with 5-fluorouracil enhances expression of carcinoembryonic antigen and susceptibility to HLA-A(*)02.01 restricted, CEA-peptide-specific cytotoxic T cells in vitro.
abstract: Cancer vaccines directed against tumor associate antigen (TAA) have produced encouraging results in preclinical models but not in cancer patients. A major limitation of this strategy is the relative degree of tolerance to these antigens and the low and heterogeneous tumor cell expression of TAA and major histocompatibility complex (MHC). Previous studies have shown that 5-fluorouracil (5-FU) can upregulate the expression of membrane-associated carcino-embryonic antigen (CEA), and MHC molecules in colon and breast carcinoma cell lines. We have investigated whether this drug can also enhance their sensitivity to the lytic effects of CEA-peptide specific Cytotoxic T cell lymphocytes (CTL). The CEA peptide-specific CTLs generated in our laboratory from normal HLA-A(*)02.01(+) donor PBMCs, were able to kill HLA-A(*)02.01(+)/CEA(+) breast (MCF-7-T103) and colon (HLA-A(*)02.01 gene-transfected HT-29 and C22.20) carcinoma cells in HLA-A(*)02.01 restricted manner. The treatment of target cells with 5-FU, enhanced their CEA expression and susceptibility to CTL-mediated lysis. Cold competition assays confirmed these results, thus supporting the hypothesis that immune target cell lysis and 5-FU mediated enhancement were dependent on CEA peptide presentation by cancer cells. 5-FU treatment of functionally "mature" CTL after in vitro expansion, did not reduce their cytolytic activity against MT-2 target cells but, when the anti-metabolite was added during the immune-sensitization phase, CTL generation was significantly inhibited. These results provide a rationale for investigating a possible new role of 5-FU as an immuno targeting amplifier agent in breast and colorectal cancer patients immunized with CEA-directed cancer vaccines.
authors.affiliation: Oncopharmacology Center, School of Medicine, University of Siena, Italy.
authors.forename: Pierpaolo
authors.initials: P
authors.lastname: Correale
authors.forename: Angelo
authors.initials: A
authors.lastname: Aquino
authors.forename: Anna
authors.initials: A
authors.lastname: Giuliani
authors.forename: Monia
authors.initials: M
authors.lastname: Pellegrini
authors.forename: Lucia
authors.initials: L
authors.lastname: Micheli
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Cusi
authors.forename: Cristina
authors.initials: C
authors.lastname: Nencini
authors.forename: Roberto
authors.initials: R
authors.lastname: Petrioli
authors.forename: Salvatore Pasquale
authors.initials: SP
authors.lastname: Prete
authors.forename: Liana
authors.initials: L
authors.lastname: De Vecchis
authors.forename: Mario
authors.initials: M
authors.lastname: Turriziani
authors.forename: Giorgio
authors.initials: G
authors.lastname: Giorgi
authors.forename: Enzo
authors.initials: E
authors.lastname: Bonmassar
authors.forename: Guido
authors.initials: G
authors.lastname: Francini
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000276:immunology; D002272:Carcinoembryonic Antigen / Q000096:biosynthesis* / Q000276:immunology; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000276:immunology; D003602:Cytotoxicity, Immunologic / Q000187:drug effects*; D005472:Fluorouracil / Q000494:pharmacology*; D015234:HLA-A Antigens / Q000276:immunology*; D006801:Humans; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D014407:Tumor Cells, Cultured
chemical_list: D000964:Antimetabolites, Antineoplastic; D002272:Carcinoembryonic Antigen; D015234:HLA-A Antigens; D005472:Fluorouracil