Co-expression of IL-15 enhances anti-neuroblastoma effectivity of a tyrosine hydroxylase-directed DNA vaccination in mice

• Published in: PloS one Vol. 13; no. 11; p. e0207320
• Main Authors: Marx, Madlen, Zumpe, Maxi, Troschke-Meurer, Sascha, Shah, Diana, Lode, Holger N, Siebert, Nikolai
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 19.11.2018; Public Library of Science (PLoS)
• Subjects: Animals; Anticancer properties; Antigen-presenting cells; Biological activity; Biology and life sciences; Bone marrow; Cancer; Cancer Vaccines - genetics; Cancer Vaccines - immunology; CD8 antigen; CD8-Positive T-Lymphocytes - immunology; CD8-Positive T-Lymphocytes - pathology; Cell growth; CHO Cells; Cricetulus; Cytokines; Cytotoxicity; Deoxyribonucleic acid; DNA; DNA vaccines; Drug dosages; Enzyme-linked immunosorbent assay; Flow cytometry; Gene expression; Gene sequencing; Gene transfer; Hematology; Humans; Hydroxylase; Immunity, Cellular; Immunization; Immunofluorescence; Immunology; Immunoregulation; Immunotherapy; Implantation; Interleukin 15; Interleukin-15 - genetics; Interleukin-15 - immunology; Lymphocytes; Lymphocytes T; Medicine; Medicine and health sciences; Metastases; Mice; Neuroblastoma; Neuroblastoma - genetics; Neuroblastoma - immunology; Neuroblastoma - pathology; Neuroblastoma - therapy; Nucleotide sequence; Oncology; Patients; Pediatrics; Plasmids; Proteins; Remission; Salmonella; Salmonella typhimurium - genetics; Salmonella typhimurium - immunology; Tumors; Tyrosine; Tyrosine 3-monooxygenase; Tyrosine 3-Monooxygenase - genetics; Tyrosine 3-Monooxygenase - immunology; Ubiquitin; Vaccination; Vaccines; Vaccines, DNA - genetics; Vaccines, DNA - immunology; Germany
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0207320

Long-term survival of high-risk neuroblastoma (NB) patients still remains under 50%. Here, we report the generation, in vitro characterization and anti-tumor effectivity of a new bicistronic xenogenic DNA vaccine encoding tyrosine hydroxylase (TH) that is highly expressed in NB tumors, and the immune stimulating cytokine interleukin 15 (IL-15) that induces cytotoxic but not regulatory T cells. The DNA sequences of TH linked to ubiquitin and of IL-15 were integrated into the bicistronic expression vector pIRES. Successful production and bioactivity of the vaccine-derived IL-15- and TH protein were shown by ELISA, bioactivity assay and western blot analysis. Further, DNA vaccine-driven gene transfer to the antigen presenting cells of Peyer's patches using attenuated Salmonella typhimurium that served as oral delivery system was shown by immunofluorescence analysis. The anti-tumor effect of the generated vaccine was evaluated in a syngeneic mouse model (A/J mice, n = 12) after immunization with S. typhimurium (3× prior and 3× after tumor implantation). Importantly, TH-/IL-15-based DNA vaccination resulted in an enhanced tumor remission in 45.5% of mice compared to controls (TH (16.7%), IL-15 (0%)) and reduced spontaneous metastasis (30.0%) compared to controls (TH (63.6%), IL-15 (70.0%)). Interestingly, similar levels of tumor infiltrating CD8+ T cells were observed among all experimental groups. Finally, co-expression of IL-15 did not result in elevated regulatory T cell levels in tumor environment measured by flow cytometry. In conclusion, co-expression of the stimulatory cytokine IL-15 enhanced the NB-specific anti-tumor effectivity of a TH-directed vaccination in mice and may provide a novel immunological approach for NB patients.