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Serve Lab
Research

Serve Lab
Research

GOETHE UNIVERSITY

GOETHE UNIVERSITY

AML
metabolism

AML
metabolism

Clonal
hematopoiesis

Therapy
resistance

Therapy
resistance

Amino acid
sensing

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Metabolism of Acute Myeloid Leukemia

Acute Myeloid Leukemia (AML) is an aggressive type of leukemia, which despite recent therapeutic progress still is fatal in the majority of cases. One important aspect of AML pathophysiology is its aggressive behavior in the bone marrow microenvironment. It has been shown that AML cells require a high degree of metabolic flexibility to adapt to the microenvironment of the bone marrow while maintaining a high proliferation rate.

In this context, we are particularly interested in the question how changes in metabolic and signaling circuits make leukemic cells more or less responsive to environmental stimuli (e.g. nutrients, cell-cell interactions, cytotoxic drugs, hypoxia).

To do this, we are using cutting-edge technologies such as CRISPR/Cas9 screening, prime editing and endogenous tagging using CRISPR/Cas9, flow cytometry and fluorescence-activated cell sorting (FACS) and in cooperation mass spectrometry- and nuclear magnetic resonance (NMR)-based metabolomics. These techniques enable us to quickly identify genetic determinants of gene expression, proliferation and survival, leukemogenicity and metabolic changes in AML cell lines and AML patient derived blasts with the goal of discovering novel clues for AML therapy.

Patient-specific/individualized/pre-therapeutic
prediction of therapy sensitivities

Treatment outcomes of AML patients are mainly limited by primary and secondary resistance mechanisms. Cellular heterogeneity and a high potential for metabolic adaptation allow AML cells to survive under therapeutic pressure. One known mechanism is the alteration of programmed cell death (apoptosis), which renders tumour cells immortal. Priming of apoptosis is mediated by the interaction network of the Bcl-2 protein family. Analysis of this network allows the identification of therapeutic sensitivities. However, a valid prediction of the sensitivity or resistance to therapy has not yet been established. For the first time, BH3 profiling, a method developed by the Letai laboratory, provided promising (pre-)clinical results for the measurement of apoptotic priming and the prediction of cell response to the intended treatment. Furthermore, the cellular dependency on individual anti-apoptotic proteins as well as their dynamic influence by co-medication (e.g. azacitidine on venetoclax effect) can be measured.
In the Serve group, we have established a standardized, FACS-based application of BH3 profiling to measure heterogeneous patient material, leading to more patient-focused medicine.

Comparative functional characterization of typical CH mutations in cardiovascular diseases and myeloid neoplasms

Clonal hematopoiesis (CH) is a common phenomenon of ageing. In the last decade in particular, CH has attracted considerable scientific and clinical interest as its occurrence is associated with cardiovascular morbidity and mortality as well as the development of myeloid neoplasia (MN). Sequencing work has shown that many CH-associated mutations are located in genes that were already known to play an important role in clonal evolution in MN. This led to the hypothesis that CH may represent a pre-leukemic state driven by the CH-associated mutations. We analyzed both publicly available and our own clinical databases of CH and cancer patients and were able to show for the first time that despite the high concordance of affected genes in CH and MN, many of these mutations occur exclusively in CH but are not found with increased frequency in MN. This observation leads to the central hypothesis of this project that different mutations in one and the same CH-associated gene have different effects on leukemogenesis, which is reflected in their occurrence or non-occurrence in MN. To test this hypothesis, we generated both types of mutations endogenously by the recently developed CRISPR-mediated cytosine base editing (CBE) and prime editing (PE) techniques.
We are analyzing these mutations in different cellular systems using the latest and most innovative technologies such as endogenous tagging, MS-based proteome analysis, ssCITEseq, CHIPseq and ATACseq. Thereby, we will contribute to a better understanding of the role of DNMT3A and TET2 as leukemia driver genes beyond their effects on clonal dominance, and we will make an important contribution to the increasingly recognized view that disease progression in CH-affected individuals can be predicted not only by the size of the affected clone, but also by the affected gene or, as in our case, by the specific variant of a particular gene

Molecular functions of amino acid sensing and processing

In the tumor microenvironment, cancer cells undergo metabolic adaptations that allow them to rapidly respond to dynamic environmental cues to meet their demands. This ability to adapt, which we currently refer to as metabolic flexibility, has been shown particularly in cells originating from Acute Myeloid Leukemia (AML).
Therefore, our research explores the molecular mechanisms by which cells can sense and respond to fluctuations in available metabolites.
In the last decade, the discovery of two GATOR complexes has significantly advanced our understanding of cellular amino acid sensing and processing mechanisms. Amino acids play a crucial role in cell proliferation as building blocks for proteins, and thus sensing of amino acids is critical for cancer cells. This underscores the indispensable role of specialized sensor protein functions, including those of GATOR1 and GATOR2, to monitor the cellular amino acid pool.

GATOR2 communicates with different cellular signaling pathways, notably with the central metabolic hub, mTORC1, thereby exerting precise control over cellular growth. In this project, we employ endogenous protein tagging using CRISPR/Cas9 technology, along with co-immunoprecipitation (CoIP) and mass spectrometry (MS) approaches, to uncover previously unexplored protein interactions and functions. Our primary goal is to extend the functional repertoire of GATOR2 and to deepen the understanding of amino acid sensing by the GATOR2 complex using insights gained from its molecular architecture. Consequently, our findings not only deepen the understanding of the GATOR2 network but also offer promising avenues for the development of targeted therapeutic strategies.

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