title: Immunosensitization of melanoma tumor cells to non-MHC Fas-mediated killing by MART-1-specific CTL cultures.
abstract: The discovery of human melanoma rejection Ags has allowed the rational design of immunotherapeutic strategies. One such Ag, MART-1, is expressed on >90% of human melanomas, and CTL generated against MART-1(27-35) kill most HLA A2.1(+) melanoma cells. However, variant tumor cells, which do not express MART-1, down-regulate MHC, or become resistant to apoptosis, will escape killing. Cytotoxic lymphocytes kill by two main mechanisms, the perforin/granzyme degranulation pathway and the TNF/Fas/TNF-related apoptosis-inducing ligand superfamily of apoptosis-inducing ligands. In this study, we examined whether cis-diaminedichloroplatinum (II) cisplatin (CDDP) sensitizes MART-1/HLA A2.1(+) melanoma and melanoma variant tumor cells to non-MHC-restricted, Fas ligand (FasL)-mediated killing by CTL. MART-1(27-35)-specific bulk CTL cultures were generated by pulsing normal PBL with MART-1(27-35) peptide. These CTL cultures specifically kill M202 melanoma cells (MART-1(+), HLA A2.1(+), FasR(-)), and MART-1(27-35) peptide-pulsed T2 cells (FasR(+)), but not M207 melanoma cells (MART-1(+), HLA A2.1(-), FasR(-)), FLU(58-66) peptide-pulsed T2 cells, or DU145 and PC-3 prostate cells (MART-1(-), HLA A2.1(-), FasR(+)). CDDP (0.1-10 microg/ml) sensitized non-MART-1(27-35) peptide-pulsed T2 to the CD8(+) subset of bulk MART-1-specific CTL, and killing was abolished by neutralizing anti-Fas Ab. Furthermore, CDDP up-regulated FasR expression and FasL-mediated killing of M202, and sensitized PC-3 and DU145 to killing by bulk MART-1-specific CTL cultures. These findings demonstrate that drug-mediated sensitization can potentiate FasL-mediated killing by MHC-restricted CTL cell lines, independent of MHC and MART-1 expression on tumor cells. This represents a novel approach for potentially controlling tumor cell variants found in primary heterogeneous melanoma tumor cell populations that would normally escape killing by MART-1-specific immunotherapy.
authors.affiliation: Department of Microbiology, Immunology and Molecular Genetics, University of California School of Medicine, University of California, Los Angeles, CA 90095, USA.
authors.forename: P J
authors.initials: PJ
authors.lastname: Frost
authors.forename: L H
authors.initials: LH
authors.lastname: Butterfield
authors.forename: V B
authors.initials: VB
authors.lastname: Dissette
authors.forename: J S
authors.initials: JS
authors.lastname: Economou
authors.forename: B
authors.initials: B
authors.lastname: Bonavida
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology; D000818:Animals; D000951:Antigens, Neoplasm; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000276:immunology*; D002478:Cells, Cultured; D002945:Cisplatin / Q000494:pharmacology; D003601:Cytotoxicity Tests, Immunologic; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D019008:Drug Resistance, Neoplasm; D000939:Epitopes / Q000378:metabolism; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D053222:Fas Ligand Protein; D006801:Humans; D006825:Hybridomas; D007114:Immunization; D058965:MART-1 Antigen; D008285:Major Histocompatibility Complex / Q000276:immunology; D008297:Male; D008545:Melanoma / Q000188:drug therapy / Q000276:immunology* / Q000378:metabolism / Q000473:pathology*; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D009363:Neoplasm Proteins / Q000276:immunology* / Q000378:metabolism; D054353:Perforin; D052899:Pore Forming Cytotoxic Proteins; D011471:Prostatic Neoplasms / Q000188:drug therapy / Q000276:immunology / Q000473:pathology; D012333:RNA, Messenger / Q000096:biosynthesis; D016176:T-Lymphocyte Subsets / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000187:drug effects / Q000276:immunology*; D014407:Tumor Cells, Cultured; D015854:Up-Regulation / Q000187:drug effects / Q000276:immunology; D019014:fas Receptor / Q000378:metabolism / Q000502:physiology*
chemical_list: D000276:Adjuvants, Immunologic; D000951:Antigens, Neoplasm; D000970:Antineoplastic Agents; D000939:Epitopes; D018984:Epitopes, T-Lymphocyte; C505661:FASLG protein, human; D053222:Fas Ligand Protein; C505658:Fasl protein, mouse; D058965:MART-1 Antigen; C105787:MART-1-Melan-A(27-35) epitope; C548667:MLANA protein, human; D008562:Membrane Glycoproteins; C548668:Mlana protein, mouse; D009363:Neoplasm Proteins; D052899:Pore Forming Cytotoxic Proteins; D012333:RNA, Messenger; D019014:fas Receptor; D054353:Perforin; D002945:Cisplatin