Friedrich Erhart1, Tamara Weiss2, Simone Klingenbrunner3, Katrin Fischhuber3, René Reitermaier3, Angela Halfmann4, Bernadette Blauensteiner4, Daniela Lötsch5, Sabine Spiegl-Kreinecker6, Walter Berger5, Fernando J Sialana7, Gert Lubec7, Thomas Felzmann8, Alexander Dohnal9, Carmen Visus3. 1. Department of Neurosurgery, Medical University of Vienna, Vienna, Austria; Institute of Neurology, Medical University of Vienna, Vienna, Austria; Department of Tumor Immunology, St. Anna Kinderkrebsforschung Children's Cancer Research Institute, Vienna, Austria. 2. Department of Tumor Biology, St. Anna Kinderkrebsforschung Children's Cancer Research Institute, Vienna, Austria. 3. Activartis Biotech GmbH, Vienna, Austria. 4. Department of Tumor Immunology, St. Anna Kinderkrebsforschung Children's Cancer Research Institute, Vienna, Austria. 5. Institute for Cancer Research, Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria. 6. University Clinic for Neurosurgery, Kepler University Hospital, Johannes Kepler University, Linz, Austria. 7. Division of Drug Design and Medicinal Chemistry, Department of Pharmaceutical Chemistry, Faculty of Life Sciences, University of Vienna, Vienna, Austria. 8. Research & Development, Central Blood Bank, Austrian Red Cross, Vienna, Austria; Activartis Biotech GmbH, Vienna, Austria. 9. Department of Tumor Immunology, St. Anna Kinderkrebsforschung Children's Cancer Research Institute, Vienna, Austria. Electronic address: alexander.dohnal@gmx.at.
Abstract
BACKGROUND: Glioblastoma is the most aggressive type of brain cancer. Dendritic cell (DC)-based immunotherapy against glioblastoma depends on the effectiveness of loaded antigens. Sphere-inducing culture conditions are being studied by many as a potential antigen source. Here, we investigated two different in vitro conditions (spheroid culture versus adherent culture) in relation to DC immunotherapy: (1) We studied the specific spheroid-culture proteome and assessed the clinical importance of spheroid proteins. (2) We evaluated the immunogenicity of spheroid lysate - both compared to adherent conditions. METHODS: We used seven spheroid culture systems, three of them patient-derived. Stemness-related markers were studied in those three via immunofluorescence. Spheroid-specific protein expression was measured via quantitative proteomics. The Cancer Genome Atlas (TCGA) survival data was used to investigate the clinical impact of spheroid proteins. Immunogenicity of spheroid versus adherent cell lysate was explored in autologous ELISPOT systems (DCs and T cells from the three patients). RESULTS: (1) The differential proteome of spheroid versus adherent glioblastoma culture conditions could successfully be established. The top 10 identified spheroid-specific proteins were associated with significantly decreased overall survival (TCGA MIT/Harvard cohort; n = 350, P = 0.014). (2) In exploratory experiments, immunogenicity of spheroid lysate vis-á-vis interferon (IFN)γ production was lower than that of adherent cell lysate (IFNγ ELISPOT; P = 0.034). CONCLUSIONS: Spheroid culture proteins seem to represent survival-relevant targets, supporting the use of spheroid culture conditions as an antigen source for DC immunotherapy. However, immunogenicity enhancement should be considered for future research. Transferability of our findings in terms of clinical impact and regarding different spheroid-generation techniques needs further validation.
BACKGROUND:Glioblastoma is the most aggressive type of brain cancer. Dendritic cell (DC)-based immunotherapy against glioblastoma depends on the effectiveness of loaded antigens. Sphere-inducing culture conditions are being studied by many as a potential antigen source. Here, we investigated two different in vitro conditions (spheroid culture versus adherent culture) in relation to DC immunotherapy: (1) We studied the specific spheroid-culture proteome and assessed the clinical importance of spheroid proteins. (2) We evaluated the immunogenicity of spheroid lysate - both compared to adherent conditions. METHODS: We used seven spheroid culture systems, three of them patient-derived. Stemness-related markers were studied in those three via immunofluorescence. Spheroid-specific protein expression was measured via quantitative proteomics. The Cancer Genome Atlas (TCGA) survival data was used to investigate the clinical impact of spheroid proteins. Immunogenicity of spheroid versus adherent cell lysate was explored in autologous ELISPOT systems (DCs and T cells from the three patients). RESULTS: (1) The differential proteome of spheroid versus adherent glioblastoma culture conditions could successfully be established. The top 10 identified spheroid-specific proteins were associated with significantly decreased overall survival (TCGA MIT/Harvard cohort; n = 350, P = 0.014). (2) In exploratory experiments, immunogenicity of spheroid lysate vis-á-vis interferon (IFN)γ production was lower than that of adherent cell lysate (IFNγ ELISPOT; P = 0.034). CONCLUSIONS: Spheroid culture proteins seem to represent survival-relevant targets, supporting the use of spheroid culture conditions as an antigen source for DC immunotherapy. However, immunogenicity enhancement should be considered for future research. Transferability of our findings in terms of clinical impact and regarding different spheroid-generation techniques needs further validation.