Reduced chromatin binding of MYC is a key effect of HDAC inhibition in MYC amplified medulloblastoma.

Abstract

BACKGROUND:

The sensitivity of myelocytomatosis oncogene (MYC) amplified medulloblastoma to class I histone deacetylase (HDAC) inhibition has been shown previously; however, understanding the underlying molecular mechanism is crucial for selection of effective HDAC inhibitors for clinical use. The aim of this study was to investigate the direct molecular interaction of MYC and class I HDAC2, and the impact of class I HDAC inhibition on MYC function.

METHODS:

Co-immunoprecipitation and mass spectrometry were used to determine the co-localization of MYC and HDAC2. Chromatin immunoprecipitation (ChIP) sequencing and gene expression profiling were used to analyze the co-localization of MYC and HDAC2 on DNA and the impact on transcriptional activity in primary tumors and a MYC amplified cell line treated with the class I HDAC inhibitor entinostat. The effect on MYC was investigated by quantitative real-time PCR, western blot, and immunofluorescence.

RESULTS:

HDAC2 is a cofactor of MYC in MYC amplified medulloblastoma. The MYC-HDAC2 complex is bound to genes defining the MYC-dependent transcriptional profile. Class I HDAC inhibition leads to stabilization and reduced DNA binding of MYC protein, inducing a downregulation of MYC activated genes (MAGs) and upregulation of MYC repressed genes (MRGs). MAGs and MRGs are characterized by opposing biological functions and by distinct enhancer-box distribution.

CONCLUSIONS:

Our data elucidate the molecular interaction of MYC and HDAC2 and support a model in which inhibition of class I HDACs directly targets MYC's transactivating and transrepressing functions.

• Authors: Jonas Ecker, Venu Thatikonda, Gianluca Sigismondo, Florian Selt, Gintvile Valinciute, Ina Oehme, Carina Müller, Juliane L Buhl, Johannes Ridinger, Diren Usta, Nan Qin, Cornelis M van Tilburg, Christel Herold-Mende, Marc Remke, Felix Sahm, Frank Westermann, Marcel Kool, Robert J Wechsler-Reya, Lukas Chavez, Jeroen Krijgsveld, Natalie Jäger, Stefan M Pfister, Olaf Witt, Till Milde
• Journal: Neuro-oncology (Neuro Oncol) Vol. 23 Issue 2 Pg. 226-239 (02 25 2021) ISSN: 1523-5866 [Electronic] England
• PMID: 32822486 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © The Author(s) 2020. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: [email protected].

Chemical References

• Chromatin
• Histone Deacetylase Inhibitors
• Histone Deacetylases

Topics

• Cell Line, Tumor
• Cerebellar Neoplasms (drug therapy, genetics)
• Chromatin
• Histone Deacetylase Inhibitors (pharmacology)
• Histone Deacetylases (genetics)
• Humans
• Medulloblastoma (drug therapy, genetics)