Cancer Autophagy Group
My research team investigates molecular mechanisms in the pathogenesis of acute myeloid leukemias and in therapy resistances of this disease. Currently, we are focusing on the role of autophagy and the transcription factor PU.1. Additional research projects led by Magali Humbert (AML) and Anna Schläfli (Breast cancer) address the function of the autophagy recycling pathway in the resistance of hematological and solid cancers against chemotherapeutic agents and targeted therapies. All these pre-clinical studies in targeted, personalized cancer therapy are conducted in close collaboration with clinical pathologists and the Translational Research Unit.
Current research projects
Function of Chaperone-Mediated Autophagy in Myeloid Leukemia Therapy
Group Tschan While classification of the heterogeneous blood cancer, acute myeloid leukemia (AML) improved significantly, scarce progress has been made in terms of treatment. Relapse and therapy failures remain high due to chemotherapy-resistant leukemic cells (CRLC). Our preliminary data link increased chaperone-mediated autophagy (CMA) to resistance mechanisms in differentiation therapy and an immature developmental stage of AML blasts. Therefore, we are aiming at understanding the role of CMA in the biology of AML cells and CRLC including the interaction with the microenvironment.
Chaperone mediated autophagy (CMA) (A) CMA signaling pathway. (B) LAMP2A and HSC70 co-localization in NB4 AML cells
Understanding the role of autophagy in retinoic acid therapy of breast cancer
Group Tschan Epithelial-to-mesenchymal transition (EMT) plays a key role in therapy-resistance and metastasis formation. In the present study, we therefore aim at reversing the EMT phenotype of breast cancer cells using differentiation-based therapy based on all-trans retinoic acid (ATRA). Cellular differentiation is often associated with upregulation of autophagy. Autophagy is a lysosomal degradation and recycling system and may supports cellular differentiation by removing superfluous organelles, keeping energy levels or by regulating signalling by selective removal of proteins. Therefore, we study autophagy functions during therapy-induced MET and how modulation of autophagy can support differentiation-based therapy. Furthermore, we investigate how cancer associated fibroblasts influence cancer autophagy and therapy efficiency.
Cancer-associated fibroblasts co-cultured with SKBR3 breast cancer cells (green). Staining: autophagy marker LC3B (red)
Identification and analysis of PU.1 cell death pathways
Group Tschan The ETS-transcription factor PU.1 is needed throughout hematopoietic differentiation particularly by orchestrating terminal differentiation of macrophages and neutrophils. Importantly, low PU.1 expression can lead to the transformation of myeloid progenitor cells to acute myeloid leukemia (AML) blast cells. We found a new tumor suppressor function for PU.1 by supporting TNF-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis in AML cells. Currently, we are investigating how PU.1 regulates alternative splicing of anti-apoptotic genes and how this affects AML therapy responses.
PU.1 in TRAIL-induced apoptosis (A) PU.1 represses NF-κB. (B) PU.1 affects expression or alternative splicing of anti-apoptotic genes