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Florian Grebien

Oncogenic Mechanisms in AML

The team of Florian Grebien aims to contribute to a better understanding of the molecular mechanisms of leukemia development through the development and use of novel tools for functional evaluation of oncogenic aberrations. Focus of his research is acute myeloid leukemia (AML), a cancer of white blood cells, characterized by the rapid growth of abnormal myeloid cells that accumulate in the bone marrow and interfere with the production of normal blood cells.

The research team of Florian Grebien with  Thomas Eder (Bioinformatician), Fabio Liberante (Postdoc), Florian Grebien (Group Leader), Christa van der Veen (Master Student), Elizabeth Heyes (PhD Student), Luisa Schmidt (PhD Student), Stefan Terlecki-Zaniewicz (PhD Student), Anna Skucha* (PhD Student), Johannes Schmöllerl (PhD Student), Jessica Ebner (PhD Student) (from left), * jointly supervised with Prof. G. Superti-Furga, CeMM Vienna

The concept of personalized treatment in modern medicine will require an improved molecular understanding of the pathological processes underlying neoplastic initiation and progression. Recent large-scale sequencing studies have revealed a high number of novel genetic lesions that may contribute to carcinogenesis. Thorough experimental validation of these newly identified mutations using standard methodologies, however, cannot keep up with the pace of continuously accelerating data generation. Therefore, the current challenge in modern biology is to adapt and develop novel tools for functional characterization of disease processes.

We are employing novel cellular expression systems in combination with cutting-edge proteomic-, genomic- and transcriptomic approaches to establish a robust experimental pipeline for the rapid characterization of effects of candidate mutations in proteins of interest in a multilayered, global fashion. This is complemented by functional studies to detect specific molecular vulnerabilities that are dependent on the oncogenic mutation of interest. Newly identified molecular mechanisms of mutated alleles are validated using primary patient-derived leukemic cells and translational mouse models of leukemia.

Schematic outline of the established experimental pipeline, inferring the proposed workflow. As indicated by the grey circle, our proposed workflow will start with an unbiased screening encompassing all gene products and will systematically reduce the number of critical candidates to manageable numbers for detailed follow-up studies.

About Florian Grebien

Since 2014 Florian Grebien leads an independent research team at the LBI-CR and is recipient of a prestigious ERC starting grant. He is an expert in the functional analysis of oncogenic pathways and as of March 2017 he has 28 PubMed based publications with more than 1.100 citations. His google scholar profile lists an h-index of 19.

FG did his PhD jointly supervised by Ernst Müllner of the Medical University Vienna and Hartmut Beug of the Research Institute for Molecular Pathology (IMP). For his post-doctoral research he joined the team of Giulio Superti-Furga at the Research Center for Molecular Medicine (CeMM), Vienna.

Please follow the link for a full CV of Florian Grebien.

Funding

Florian Grebien's research is funded with a start-up package from institute ressources to support the development of his independent research programme. Since June 2015 his research is in addition funded by the starting grant "ONCOMECHAML" from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No. 636855). In this five year project he will deploy an innovative combination of modern methods to identify key molecules that can be used as a basis for the development of new therapies. The reviewers of the proposal confirmed in their evaluation statement, that his approach is clinically relevant and feasibly will lead to the development of a novel concept in research.
In addition his research is supported by the Austrian Academy of Sciences through prestigious DOC fellowships towards Luisa Schmidt and Johannes Schmöllerl. Finally the Austrian Research Promotion Agency (FFG) financially supports project #857935 entitled "Characterization of small molecules for targeted degradation of WDR5 to interfere with oncogenic MLL activity in cancer".

  

Functional Studies in AML

Systematic functional interrogation of conserved interaction partners of MLL fusion proteins. (A) AP-MS-derived protein-protein interaction network of 7 selected MLL fusion proteins (schematic fusion proteins). Shown are top 300 interactors per fusion protein (based on p-values, grey and cyan circles). Cyan circles represent 128 proteins that interact with ≥5 of 7 MLL fusion proteins.

Comprehensive Functional Studies on Translocation Products in AML

Chromosomal translocations are frequent events in leukemia. Often, this event fuses two genes, thereby creating novel proteins with oncogenic functions. In many cases, the molecular mechanism of cellular transformation of these translocation products is unknown. We have already established a number of cancer cell lines with inducible expression of affinity tagged variants of translocation products for  a comprehensive analysis of their oncogenic activities.

Critical Effectors of NUP98 Fusions in AML

Comparative analysis of four selected NUP98-fusion proteins using a mouse bone marrow transplantation model: Bioluminescence imaging of secondary recipient mice transplanted with primary NUP98-FP AML cells in the absence or presence of Dox.

A significant number of genes is involved in a series of cytogenetically distinct translocation events involving more than one fusion partner gene, resulting in “Multi-Partner Translocation (MPT) families”. MPT families share the biochemical properties of one common partner moiety, but at the same time feature very different functions of the unique fusion partner gene parts. An important MPT family in AML comprises fusions involving the NUP98 (Nucleoporin 98) gene, featuring >20 different fusion proteins.

C/EBPa mutations in AML

C/EBPa mutations in AML

Nine percent of patients with Acute Myeloid leukemia (AML) have mutations in the gene encoding the transcription factor CCAAT-enhancer-binding protein alpha (C/EBPa, CEBPA). Although it is known that these mutations induce a block in myeloid differentiation and lead to increased self renewal, the molecular mechanisms underlying these changes are still poorly understood. In the recent past, we have established a number of cell line models that allow functional studies of CEBPA mutations. We are now employing shRNA- and drug screening approaches to identify critical vulnerable points in CEBPA-mutant AML development and progression.

Collaborations

National

Keiryn Bennett, CeMM Vienna: Mass Spectrometry/Proteomics

Michael Dworzak, Children's Cancer Research Institute, Vienna, Austria: Mechanistic studies on primary human AML cells.

Stefan Kubicek, CeMM Vienna, PLACEBO: Drug Screening, Chemical Biology

Peter Valent, Medical University Vienna: Clinical Aspects of Leukemia, Leukemic Stem Cells

Veronika Sexl, University of Veterinary Medicine, Vienna: Molecular mechanisms of leukemogenesis.