USP8 controls proteostasis pathways in B cells and multiple myeloma

Leukemia

Abstract

Abstract Ubiquitin-specific protease 8 (USP8) plays a pivotal role in the regulation of endosomal and lysosomal trafficking and is critically involved in the pathogenesis of various tumor entities. USP8 represents a vulnerability gene in multiple myeloma (MM), suggesting a functional role in the B- and plasma cell compartment. Here we analyzed mice with stage-specific Usp8 deletion during B-cell development and investigated its role in patient-derived MM cells that are sensitive or resistant to the proteasome inhibitor Bortezomib (BTZ) using USP8 depletion and treatment with DUB-IN-2, a reported USP8 inhibitor. Usp8 depletion in Usp8 f/f C d19 -Cre mice affected B-cell survival and development favoring immature, innate-like B cells, and germinal center and plasma cells, while also elevating immune-responses and causing Roquin depletion. Cells expressing catalytically inactive USP8 accumulated proteins modified with mixed ubiquitin/NEDD8 chains indicative of proteotoxic stress, which we identified as preferred USP8 substrates. In MM cells, USP8 knockdown reduced survival via lysosomal dysfunction. In contrast, DUB-IN-2 induced an enhanced ER stress response to treatment with BTZ questioning DUB-IN-2 function as a USP8 inhibitor, as confirmed by biochemical analysis. Thus, our results highlight the therapeutic potential of targeting USP8 and identify the combination of DUB-IN-2 and BTZ as a novel strategy for treating BTZ-resistant MM.

Authors 22

1. Almut Dufner corresponding

   University of Freiburg · University Medical Center Freiburg

   Affiliation as printed

   Institute of Neuropathology, Medical Center-University of Freiburg/Medical Faculty - University of Freiburg, Freiburg, Germany. almut.dufner@uniklinik-freiburg.de

2. Fabien Théry

   Ghent University · VIB-UGent Center for Medical Biotechnology

   Affiliation as printed

   Department of Biomolecular Medicine, Gent, Belgium

   VIB-UGent Center for Medical Biotechnology, Gent, Belgium

3. Gianni Monaco

   University of Freiburg · University Medical Center Freiburg

   Affiliation as printed

   Institute for Transfusion Medicine and Gene Therapy, Medical Center - University of Freiburg/Medical Faculty - University of Freiburg, Freiburg, Germany

   Institute of Neuropathology, Medical Center-University of Freiburg/Medical Faculty - University of Freiburg, Freiburg, Germany

4. Jelena Lazarevic Aachen Department of Hematology, Oncology

   RWTH Aachen University · Universitätsklinikum Aachen

   Affiliation as printed

   Department of Hematology, Oncology, Hemostaseology and Stem Cell Transplantation University Hospital RWTH Aachen, Aachen, Germany

5. Oliver Gorka

   University of Freiburg · University Medical Center Freiburg

   Affiliation as printed

   Institute of Neuropathology, Medical Center-University of Freiburg/Medical Faculty - University of Freiburg, Freiburg, Germany

6. Nina Chevalier

   University of Freiburg · University Medical Center Freiburg

   Affiliation as printed

   Department of Rheumatology and Clinical Immunology, Medical Center - University of Freiburg/Medical Faculty - University of Freiburg, Freiburg, Germany

7. Marta Campos Alonso

   University of Freiburg · University Medical Center Freiburg

   Affiliation as printed

   Institute of Neuropathology, Medical Center-University of Freiburg/Medical Faculty - University of Freiburg, Freiburg, Germany

8. Maximilian Frosch

   University of Freiburg · University Medical Center Freiburg

   Affiliation as printed

   Institute of Neuropathology, Medical Center-University of Freiburg/Medical Faculty - University of Freiburg, Freiburg, Germany

9. Gerbrand J. van der Heden van Noort

   Leiden University Medical Center

   Affiliation as printed

   Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands

10. Kira Allmeroth

    Max Planck Institute for Biology of Ageing

    Affiliation as printed

    Max Planck Institute for Biology of Ageing, Cologne, Germany

11. Marco Prinz

    University of Freiburg · University Medical Center Freiburg

    Affiliation as printed

    Center for Basics in NeuroModulation (NeuroModulBasics), Medical Center - University of Freiburg/Medical Faculty - University of Freiburg, Freiburg, Germany

    Institute of Neuropathology, Medical Center-University of Freiburg/Medical Faculty - University of Freiburg, Freiburg, Germany

    Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany

12. Olaf Groß

    University of Freiburg · University Medical Center Freiburg

    Affiliation as printed

    Center for Basics in NeuroModulation (NeuroModulBasics), Medical Center - University of Freiburg/Medical Faculty - University of Freiburg, Freiburg, Germany

    Institute of Neuropathology, Medical Center-University of Freiburg/Medical Faculty - University of Freiburg, Freiburg, Germany

    Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany

13. Huib Ovaa

    Leiden University Medical Center

    Affiliation as printed

    Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands

14. Paul P. Geurink

    Leiden University Medical Center

    Affiliation as printed

    Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands

15. Wolfgang W. Schamel

    University of Freiburg · University Medical Center Freiburg

    Affiliation as printed

    Center of Chronic Immunodeficiency CCI, Medical Center - University of Freiburg/Medical Faculty - University of Freiburg, Freiburg, Germany

    Faculty of Biology, Albert-Ludwigs-University of Freiburg, Freiburg, Germany

    Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany

16. Martin S. Denzel

    University of Cologne · Cologne Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases · Max Planck Institute for Biology of Ageing

    Affiliation as printed

    CECAD - Cluster of Excellence, University of Cologne, Cologne, Germany

    Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany

    Max Planck Institute for Biology of Ageing, Cologne, Germany

17. Vigo Heissmeyer

    Ludwig-Maximilians-Universität München · Helmholtz Munich

    Affiliation as printed

    Institute for Immunology, Biomedical Center, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany

    Research Unit Molecular Immune Regulation, Helmholtz Zentrum München, Munich, Germany

18. Bénédikt Jacobs

    Friedrich-Alexander-Universität Erlangen-Nürnberg · Universitätsklinikum Erlangen

    Affiliation as printed

    Department of Internal Medicine 5, Hematology and Oncology, Friedrich Alexander University Erlangen-Nuremberg (FAU) and Universitätsklinikum Erlangen, Erlangen, Germany

19. Mirle Schemionek Aachen Department of Hematology, Oncology

    RWTH Aachen University · Universitätsklinikum Aachen · Hochschule Bonn-Rhein-Sieg

    Affiliation as printed

    Department of Hematology, Oncology, Hemostaseology and Stem Cell Transplantation University Hospital RWTH Aachen, Aachen, Germany

    Institute for Functional Gene Analytics (IFGA), Bonn-Rhein-Sieg University of Applied Sciences, Rheinbach, Germany

20. Francis Impens

    Ghent University · VIB-UGent Center for Medical Biotechnology

    Affiliation as printed

    Department of Biomolecular Medicine, Gent, Belgium

    VIB Proteomics Core, Gent, Belgium

    VIB-UGent Center for Medical Biotechnology, Gent, Belgium

21. Heiko Bruns

    Friedrich-Alexander-Universität Erlangen-Nürnberg · Universitätsklinikum Erlangen

    Affiliation as printed

    Department of Internal Medicine 5, Hematology and Oncology, Friedrich Alexander University Erlangen-Nuremberg (FAU) and Universitätsklinikum Erlangen, Erlangen, Germany

22. Klaus‐Peter Knobeloch corresponding

    University of Freiburg · University Medical Center Freiburg

    Affiliation as printed

    Institute of Neuropathology, Medical Center-University of Freiburg/Medical Faculty - University of Freiburg, Freiburg, Germany. klaus-peter.knobeloch@uniklinik-freiburg.de

    Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany. klaus-peter.knobeloch@uniklinik-freiburg.de