Research

Success rates in treatment of Osteosarcoma (OS), an aggressive cancer with many fatalities in affected children and adolescents, have not improved over the last 40 years. In view of the sizable number of OS-associated mutations and opportunities provided by innovation-driven personalized T-cell-based biomedicine with ever-increasing curative potential, such stalemate is no longer acceptable. As a therapeutic anchor point, OS-related tumor antigens (TAs; both tumor-associated and tumor-specific neoantigens) are displayed on tumors via MHC molecules as short peptides for surveillance by TA-specific tumor-infiltrating CD4+ helper and CD8+ cytotoxic T cells (TILs, CTLs). If equipped and unless undercut by tumor immune evasion mechanisms with adequate TCRs, antigen-scanning CTLs are poised to kill targets in the presence of even a single antigenic peptide/MHC complex (pMHC). Considering the complexities characterizing interactions between OS and the T-cell compartment yet also the limits on TCR-reactivity set by negative thymic selection, we predict that achieving game-changing breakthroughs mandates a highly concerted multidisciplinary approach. To this end our team will combine its considerable expertise in cancer biology, T-cell and molecular immunology as well as in biotechnology and systems biology. More specifically, we seek to identify personal OS-associated antigens and their matching TA-specific TCRs as well as T-cell and OS-intrinsic regulatory mechanisms underlying immune evasion to ultimately engineer autologous CTLs with enhanced tumor clearing capacity and find entry points for OS-preconditioning in immunotherapy. For this we will express recombinant tumor-enriched “orphan” TCRs isolated from TILs of OS patients to screen yeast-displayed peptide/MHC (pMHC) libraries with vast epitope coverage for nominal TAs. As a complementary approach we will first classify T-cell epitopes based on their relevance for tumor lysis and then determine cognate TCR matches. Following functional validation of TCR-epitope matches in vitro, in tumor sections and in vivo, we will combine computational, biophysical and protein engineering approaches to derive functionally enhanced patient-specific TCRs. In parallel, to inform the design of TME-resilient T-cells and drug-based OS-preconditioning for effective immunotherapies, we seek to delineate through CRISPR-Cas9- and DNA-barcoding-based screening T-cell- and OS-intrinsic mechanisms underlying immune evasion. Will focus on OS-related strategies to interfere with surface expression and TCR-accessibility of MHC class I. We further intend to identify as of yet unknown T-cell- and OS-intrinsic pathways undermining CTL-antigen sensitivity and effector function for improved therapeutic intervention. We expect to lay the foundation and streamline curative OS treatment in Austria and beyond and to pioneer effective and low-toxicity targeting of other solid tumor entities.

The mammalian immune system possesses a remarkable ability to discern self from non-self, a critical function in safeguarding against infections. At the molecular level, this discrimination is facilitated by pattern recognition receptors present on eukaryotic cells, which can identify conserved non-self molecules characteristic of microorganisms. Among these molecules, lipopolysaccharide (LPS) stands out as a complex glycolipid abundantly present in Gram-negative bacterial cell wall, playing a central role in host-pathogen interaction. LPS is universally recognised by specific innate immune proteins that elicit a beneficial pro-inflammatory defense response to infection while maintaining immune homeostasis. However, bacterial pathogens possess various mechanisms to adapt their cell membranes in response to transmission between the environment, vectors, and human hosts, often altering LPS composition to modulate the host immune response. In particular, modifications to the phosphate groups of lipid A, the major immunostimulatory component of LPS, can shield bacteria from recognition by host cationic antimicrobial peptides. Yet, the impact of such modifications on LPS-specific pattern recognition receptors of the host innate immune system remains largely unexplored, particularly with regard to the recently identified cytosolic LPS-sensing proteins crucial for anti-tumor immunity. Due to the high heterogeneity of bacterial glycans and the inherent instability of modified phosphate groups, the isolation of structurally defined intact LPS fragments from bacterial sources is not feasible. Chemical synthesis, however, is a reliable method for providing molecularly defined immunomodulatory LPS motifs to study the effects of unique phosphate group modifications on the interaction with host immune receptors involved in antitumour defence. Carbohydrate chemistry, or glycochemistry, offers versatile tools for the synthesis of complex glycans, providing structurally defined, homogeneous molecules of high purity suitable for biological studies. Leveraging the glycochemistry toolbox, our project aims to develop innovative synthetic strategies for the assembly of complex phosphorylated glycans, culminating in a library of bacterial LPS motifs with phosphate group modifications reflecting those found in different bacterial species. In collaboration with international research groups in immunology and structural biology, we will investigate the immunobiological activity and interaction of our synthetic phosphorylated glycolipid-glycan library with corresponding proteins. By developing a collection of synthetic bacterial lipid A variants and LPS epitopes with uniquely modified phosphate groups, our research aims to elucidate the structural and molecular basis of their interaction with host innate immune receptors, thereby advancing our understanding of LPS-induced antibacterial defense and antitumor immunity mechanisms.

The HistoGenes project unites historians, archaeologists, geneticist, anthropologists, and specialists in bio-informatics, isotope analysis and other scientific methods in order to investigate human migration in the Carpathian Basin after the break down of the Roman Empire 400-900 CE. www.histogenes.org The Institute of Analytical Chemistry (IAC) at the University of Natural Resources and Life Sciences, Vienna will perform the analysis of strontium isotopic n(87Sr)/n(86Sr) ratios and multi-elemental patterns of teeth from individuals excavated at two Awar cemeteries in Austria. Furthermore, the IAC will cooperate with the other beneficiaries for interpretation of the results, which can only be done in an interdisciplinary team due to the complexity of the burial site. The gained information will allow to understand if individuals were local or migrated. This will advance our knowledge about population dynamics in a key period in European history.