title: Targeting of MYCN by means of DNA vaccination is effective against neuroblastoma in mice.
abstract: The MYCN oncogene is a strong genetic marker associated with poor prognosis in neuroblastoma (NB). Therefore, MYCN gene amplification and subsequent overexpression provide a possible target for new treatment approaches in NB. We first identified an inverse correlation of MYCN expression with CD45 mRNA in 101 NB tumor samples. KEGG mapping further revealed that MYCN expression was associated with immune-suppressive pathways characterized by a down-regulation of T cell activation and up-regulation of T cell inhibitory gene transcripts. We then aimed to investigate whether DNA vaccination against MYCN is effective to induce an antigen-specific and T cell-mediated immune response. For this purpose, we generated a MYCN-expressing syngeneic mouse model by MYCN gene transfer to NXS2 cells. MYCN-DNA vaccines were engineered based on the pCMV-F3Ub plasmid backbone to drive ubiquitinated full-length MYCN-cDNA and minigene expression. Vaccines were delivered orally with attenuated S. typhimurium strain SL7207 as a carrier. Immunization with both MYCN-DNA vaccines significantly reduced primary tumor growth of MYCN-expressing NB cells in contrast to negative controls. The immune response was mediated by tumor-infiltrating T cells in vivo, which revealed MYCN-specific and MHC class I-restricted lysis of inducible MYCN-expressing NB target cells in vitro. Finally, these antigen-specific T cells also killed MYCN-negative mammary carcinoma cells pulsed with MYCN peptides in contrast to controls. In summary, we demonstrate proof of concept that MYCN can be targeted by DNA vaccination, which may provide an approach to overcoming MYCN immune-suppressive activities in patients with MYCN-amplified disease.
authors.affiliation: Pediatric Hematology and Oncology, University Medicine Greifswald, Ferdinand-Sauerbruch-Str 1, 17475, Greifswald, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Stermann
authors.forename: Nicole
authors.initials: N
authors.lastname: Huebener
authors.forename: Diana
authors.initials: D
authors.lastname: Seidel
authors.forename: Stefan
authors.initials: S
authors.lastname: Fest
authors.forename: Georg
authors.initials: G
authors.lastname: Eschenburg
authors.forename: Michael
authors.initials: M
authors.lastname: Stauder
authors.forename: Alexander
authors.initials: A
authors.lastname: Schramm
authors.forename: Angelika
authors.initials: A
authors.lastname: Eggert
authors.forename: Holger N
authors.initials: HN
authors.lastname: Lode
mesh_terms: D000284:Administration, Oral; D000818:Animals; D002277:Carcinoma / Q000276:immunology* / Q000382:microbiology; D045744:Cell Line, Tumor; D003602:Cytotoxicity, Immunologic; D018985:Epitopes, B-Lymphocyte / Q000235:genetics / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology*; D015674:Mammary Neoplasms, Animal / Q000276:immunology* / Q000382:microbiology; D051379:Mice; D008815:Mice, Inbred Strains; D000071447:N-Myc Proto-Oncogene Protein; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental; D009447:Neuroblastoma / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D010446:Peptide Fragments; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D022562:Salmonella Vaccines / Q000008:administration & dosage*; D012486:Salmonella typhimurium / Q000276:immunology*; D019076:Transgenes / Q000235:genetics; D047368:Tumor Burden; D014611:Vaccination; D014613:Vaccines, Attenuated / Q000008:administration & dosage*; D019444:Vaccines, DNA / Q000008:administration & dosage*
chemical_list: D018985:Epitopes, B-Lymphocyte; C571825:MYCN protein, mouse; D000071447:N-Myc Proto-Oncogene Protein; D010446:Peptide Fragments; D011518:Proto-Oncogene Proteins; D022562:Salmonella Vaccines; D014613:Vaccines, Attenuated; D019444:Vaccines, DNA