title: EWS-FLI-1-targeted cytotoxic T-cell killing of multiple tumor types belonging to the Ewing sarcoma family of tumors.
abstract: OBJECTIVE
  The Ewing sarcoma family of tumors (ESFT) comprises a group of aggressive, malignant bone, and soft tissue tumors that predominantly affect children and young adults. These tumors frequently share expression of the EWS-FLI-1 translocation, which is central to tumor survival but not present in healthy cells. In this study, we examined EWS-FLI-1 antigens for their capacity to induce immunity against a range of ESFT types.
  
  
  METHODS
  Computer prediction analysis of peptide binding, HLA-A2.1 stabilization assays, and induction of cytotoxic T-lymphocytes (CTL) in immunized HLA-A2.1 transgenic mice were used to assess the immunogenicity of native and modified peptides derived from the fusion region of EWS-FLI-1 type 1. CTL-killing of multiple ESFT family members in vitro, and control of established xenografts in vivo, was assessed. We also examined whether these peptides could induce human CTLs in vitro.
  
  
  RESULTS
  EWS-FLI-1 type 1 peptides were unable to stabilize cell surface HLA-A2.1 and induced weak CTL activity against Ewing sarcoma cells. In contrast, peptides with modified anchor residues induced potent CTL killing of Ewing sarcoma cells presenting endogenous (native) peptides. The adoptive transfer of CTL specific for the modified peptide YLNPSVDSV resulted in enhanced survival of mice with established Ewing sarcoma xenografts. YLNPSVDSV-specific CTL displayed potent killing of multiple ESFT types in vitro: Ewing sarcoma, pPNET, Askin's Tumor, and Biphenotypic sarcoma. Stimulation of human peripheral blood mononuclear cells with YLNPSVDSV peptide resulted in potent CTL-killing.
  
  
  CONCLUSIONS
  These data show that YLNPSVDSV peptide is a promising antigen for ESFT immunotherapy and warrants further clinical development.
authors.affiliation: Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
authors.forename: Christopher H
authors.initials: CH
authors.lastname: Evans
authors.forename: Fangjun
authors.initials: F
authors.lastname: Liu
authors.forename: Ryan M
authors.initials: RM
authors.lastname: Porter
authors.forename: Regina P
authors.initials: RP
authors.lastname: O'Sullivan
authors.forename: Taha
authors.initials: T
authors.lastname: Merghoub
authors.forename: Elaine P
authors.initials: EP
authors.lastname: Lunsford
authors.forename: Kyle
authors.initials: K
authors.lastname: Robichaud
authors.forename: Frans
authors.initials: F
authors.lastname: Van Valen
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Lessnick
authors.forename: Mark C
authors.initials: MC
authors.lastname: Gebhardt
authors.forename: James W
authors.initials: JW
authors.lastname: Wells
mesh_terms: D000328:Adult; D000818:Animals; D045744:Cell Line, Tumor; D015972:Gene Expression Regulation, Neoplastic; D015789:HLA-A2 Antigen / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007167:Immunotherapy; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D015514:Oncogene Proteins, Fusion / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D010455:Peptides / Q000235:genetics / Q000276:immunology*; D012512:Sarcoma, Ewing / Q000188:drug therapy / Q000276:immunology / Q000473:pathology; D015398:Signal Transduction; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology / Q000502:physiology; D023041:Xenograft Model Antitumor Assays
chemical_list: C524590:EWS-FUS protein, human; D015789:HLA-A2 Antigen; D015514:Oncogene Proteins, Fusion; D010455:Peptides