Kovar Group

The search for the right medication

The central genetic aberration of Ewing sarcoma is a gene fusion that results in the production of a disease-driving aberrant gene regulatory protein, EWS-FLI1. This fusion protein is toxic to most tissues, and the cell type and developmental stage giving rise to EWS-FLI1-driven Ewing sarcoma pathogenesis remains an enigma. The overall aim of our research is to identify druggable vulnerabilities in the molecular pathways that drive Ewing sarcoma pathogenesis. Since transcription factors – such as EWS-FLI1 – have thus far represented rather inaccessible therapeutic targets, we want to decode the molecules and biochemical pathways, which are active up- and downstream of EWS-FLI1 and are modulating EWS-FLI1 expression and its effects. We are assessing this goal through a multidisciplinary systems approach using experimental perturbation in tumor cell lines, mesenchymal stem cells, and innovative in vitro and in vivo models by gene editing and compound screening strategies with validation in primary tumor samples.

To accelerate drug development, our group in close collaboration with the Medical (Departments of Pediatric Surgery, Thoracic Surgery , and of Pathology – M. Metzelder, T. Schweiger, G. Amann) and the Technical (Group 3D Printing and Biofabrication – A. Ovsianikov) Universities of Vienna is developing 3D-bioprinted and organoid-based culture systems for pediatric solid tumors. We are particularly interested in the reconstruction of lung metastases, the most frequent complication during disease progression. With support of H. Clevers´s group (M. van de Wetering) at Prinses Máxima Center in the Netherlands we seek to establish scalable and standardized in vitro tumor models that recapitulate the physical and cellular microenvironment of the metastatic niche for high-throughput drug screenings.

Unraveling the origins of Ewing sarcoma

After hypothesis-generating in vitro studies, preclinical drug development requires validation in in vivo models which closely recapitulate the human disease. For Ewing sarcoma, such models are largely lacking as the tissue and developmental stage of origin are still unknown. There is previous evidence that it may arise from some mesodermal or neural crest-derived mesenchymal cell type. As Ewing sarcoma presents predominantly during puberty, we are studying the impact of hormones and other endocrine factors on EWS-FLI1-driven tumorigenesis from embryonal mesenchymal stem cell-like cells in the mouse in the context of a European IMI2 funded project (ITCC-P4). In addition, together with F. Halbritter´s group at CCRI, we are generating a single-cell roadmap of normal and EWS-FLI1-perturbed human mesenchymal stem cell differentiation to screen for cell types and differentiation stages most closely resembling primary Ewing sarcoma cells. This study is part of a collaborative project with the Medical University of Vienna (Departments of Dermatology and of Neuroimmunology – M. Farlik and I. Adameyko) and the University of Natural Resources and Life Sciences (Institute of Cell and Tissue Culture Technologies – C. Kasper), generously funded by the “Crazy8” program of the US-based Alex´s Lemonade Stand Foundation (ALSF). As a second component of this project in close collaboration with M. Distel´s group at CCRI, we are making use of the Ewing sarcoma epigenetic memory in a trans-species approach to screen for cell types and developmental stages in the zebrafish, in which Ewing sarcoma specific transcriptional enhancers are active. These cells will be molecularly characterized in great detail and used to drive tumorigenesis in fish by introduction of EWS-FLI1. The transcriptomic fingerprint of these cells will serve to screen for similar cell types in mice and humans.

• Tracking Ewing sarcoma origin by developmental and trans-species genomics (ORIGIN)
  CCRI responsible Principal Investigator and Coordinator: Heinrich Kovar
  Additional CCRI Collaborators: Martin Distel, Florian Halbritter
  Grant from Alex’s Lemonade Stand Foundation (ALSF), Crazy 8 Initiative Award Program
  Duration: 01/03/2021 to 28/02/2025

• Validation of Actionable Genomic Aberrations in a Paediatric Oncology Network for Doctorate students (VAGABOND)
  CCRI responsible Principal Investigator: Heinrich Kovar
  Coordinator: Jan Molenaar (Prinses Máxima Centrum, the Netherlands)
  Grant from the European Union, H2020 – MSCA Innovative Training Networks, ID – 956285
  Duration: 01/12/2020 to 30/11/2024

• ITCC Pediatric Preclinical POC Platform (ITCCP4)
  CCRI responsible Principal Investigator: Heinrich Kovar
  Coordinator: Stefan Pfister (Deutsches Krebsforschungszentrum DKFZ, Germany)
  Grant from the Innovative Medicines Initiative (IMI), ID – 116064
  Duration: 01/01/2017 to 31/12/2023

• EWS-FLI1 fluctuations in Ewing Sarcoma
  CCRI responsible Principal Investigator: Heinrich Kovar
  Grant from the Austrian Science Fund (FWF), Stand-Alone Project, ID – P 34341
  Duration: 01/04/2021 to 31/03/2024

• MetLung, an innovative 3D lung metastasis model
  CCRI responsible Principal Investigator and Coordinator: Heinrich Kovar
  Grant from the Austrian Science Fund (FWF) & Federal Ministry of Education, Science and Research (BMBWF), ID – P 35353
  Duration: 02/05/2022 to 01/05/2025