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Published in: Journal of Hematology & Oncology 1/2018

Open Access 01-12-2018 | Research

Cyclin D1-CDK4 activity drives sensitivity to bortezomib in mantle cell lymphoma by blocking autophagy-mediated proteolysis of NOXA

Authors: Simon Heine, Markus Kleih, Neus Giménez, Kathrin Böpple, German Ott, Dolors Colomer, Walter E. Aulitzky, Heiko van der Kuip, Elisabeth Silkenstedt

Published in: Journal of Hematology & Oncology | Issue 1/2018

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Abstract

Background

Mantle cell lymphoma (MCL) is an aggressive B-non-Hodgkin lymphoma with generally poor outcome. MCL is characterized by an aberrantly high cyclin D1-driven CDK4 activity. New molecular targeted therapies such as inhibitors of the ubiquitin-proteasome system (UPS) have shown promising results in preclinical studies and MCL patients. Our previous research revealed stabilization of the short-lived pro-apoptotic NOXA as a critical determinant for sensitivity to these inhibitors. It is currently unclear how cyclin D1 overexpression and aberrant CDK4 activity affect NOXA stabilization and treatment efficacy of UPS inhibitors in MCL.

Methods

The effect of cyclin D1-driven CDK4 activity on response of MCL cell lines and primary cells to proteasome inhibitor treatment was investigated using survival assays (Flow cytometry, AnnexinV/PI) and Western blot analysis of NOXA protein. Half-life of NOXA protein was determined by cycloheximide treatment and subsequent Western blot analysis. The role of autophagy was analyzed by LC3-II protein expression and autophagolysosome detection. Furthermore, silencing of autophagy-related genes was performed using siRNA and MCL cells were treated with autophagy inhibitors in combination with proteasome and CDK4 inhibition.

Results

In this study, we show that proteasome inhibitor-mediated cell death in MCL depends on cyclin D1-driven CDK4 activity. Inhibition of cyclin D1/CDK4 activity significantly reduced proteasome inhibitor-mediated stabilization of NOXA protein, mainly driven by an autophagy-mediated proteolysis. Bortezomib-induced cell death was significantly potentiated by compounds that interfere with autophagosomal function. Combined treatment with bortezomib and autophagy inhibitors enhanced NOXA stability leading to super-induction of NOXA protein. In addition to established autophagy modulators, we identified the fatty acid synthase inhibitor orlistat to be an efficient autophagy inhibitor when used in combination with bortezomib. Accordingly, this combination synergistically induced apoptosis both in MCL cell lines and in patient samples.

Conclusion

Our data demonstrate that CDK4 activity in MCL is critical for NOXA stabilization upon treatment with UPS inhibitors allowing preferential induction of cell death in cyclin D transformed cells. Under UPS blocked conditions, autophagy appears as the critical regulator of NOXA induction. Therefore, inhibitors of autophagy are promising candidates to increase the activity of proteasome inhibitors in MCL.
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Literature
12.
go back to reference Doorduijn JK, Minnema MC, Kersten MJ, Lugtenburg PJ, Schipperus MR, van Marwijk Kooy M, et al. Bortezomib maintenance therapy after induction with R-CHOP, ARA-C and autologous stem cell transplantation in newly diagnosed MCL patients, results of a multicenter phase II HOVON study. Blood. 2015;23:339. Doorduijn JK, Minnema MC, Kersten MJ, Lugtenburg PJ, Schipperus MR, van Marwijk Kooy M, et al. Bortezomib maintenance therapy after induction with R-CHOP, ARA-C and autologous stem cell transplantation in newly diagnosed MCL patients, results of a multicenter phase II HOVON study. Blood. 2015;23:339.
Metadata
Title
Cyclin D1-CDK4 activity drives sensitivity to bortezomib in mantle cell lymphoma by blocking autophagy-mediated proteolysis of NOXA
Authors
Simon Heine
Markus Kleih
Neus Giménez
Kathrin Böpple
German Ott
Dolors Colomer
Walter E. Aulitzky
Heiko van der Kuip
Elisabeth Silkenstedt
Publication date
01-12-2018
Publisher
BioMed Central
Published in
Journal of Hematology & Oncology / Issue 1/2018
Electronic ISSN: 1756-8722
DOI
https://doi.org/10.1186/s13045-018-0657-6

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