Abstract
Purpose: The epigenetic mechanisms involved in transcriptional regulation leading to malignant phenotype in gliomas remains poorly understood. Topoisomerase IIB (TOP2B), an enzyme that decoils and releases torsional forces in DNA, is overexpressed in a subset of gliomas. Therefore, we investigated its role in epigenetic regulation in these tumors. Experimental Design: To investigate the role of TOP2B in epigenetic regulation in gliomas, we performed paired chromatin immunoprecipitation sequencing for TOP2B and RNA-sequencing analysis of glioma cell lines with and without TOP2B inhibition and in human glioma specimens. These experiments were complemented with assay for transposase-accessible chromatin using sequencing, gene silencing, and mouse xenograft experiments to investigate the function of TOP2B and its role in glioma phenotypes. Results: We discovered that TOP2B modulates transcription of multiple oncogenes in human gliomas. TOP2B regulated transcription only at sites where it was enzymatically active, but not at all native binding sites. In particular, TOP2B activity localized in enhancers, promoters, and introns of PDGFRA and MYC, facilitating their expression. TOP2B levels and genomic localization was associated with PDGFRA and MYC expression across glioma specimens, which was not seen in nontumoral human brain tissue. In vivo, TOP2B knockdown of human glioma intracranial implants prolonged survival and downregulated PDGFRA. Conclusions: Our results indicate that TOP2B activity exerts a pleiotropic role in transcriptional regulation of oncogenes in a subset of gliomas promoting a proliferative phenotype.
Original language | English (US) |
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Pages (from-to) | 5669-5680 |
Number of pages | 12 |
Journal | Clinical Cancer Research |
Volume | 27 |
Issue number | 20 |
DOIs | |
State | Published - Oct 15 2021 |
Funding
E. Gonzalez-Buendia reports grants from CONACYT during the conduct of the study and a patent for Therapeutic Modulation of Oncogenes by Pharmacologic TOP2 Targeting for Cancer pending. E. Feldstein reports a patent for WO2018094325A1 issued. J.N. Sarkaria reports grants from Basilea, Glaxo Smith Kline, Bristol Myers Squibb, Curtana, Forma, AbbVie, Actuate Boehringer Ingelheim, Celgene, Cible, Wayshine, Boston Scientific, AstraZeneca, Black Diamond, Karyopharm, and Bayer outside the submitted work. D.J. Brat reports grants from NCI during the conduct of the study. R. Rabadan reports other support from Genotwin and personal fees from Aimedbio outside the submitted work. No disclosures were reported by the other authors. We acknowledge the technical assistance of Nervous System Tumor Bank (NSTB), Mouse Histology and Phenotyping Laboratory (MHPL), Center for Advanced Microscopy (CAM) and Flow Cytometry Core (RHLCCC). This work was funded by 5DP5OD021356-05 (to A.M. Sonabend), P50CA221747 SPORE for Translational Approaches to Brain Cancer (to M. Lesniak), developmental funds from The Robert H. Lurie NCI Cancer Center Support Grant No. P30CA060553 (to A. Sonabend) and, CONACyT Postdoctoral fellowship CVU207989 (to E. Gonzalez-Buendia). We thank Dr. Paul Fisher (Stony Brook University Medical School, Stony Brook, New York) for the kind gift of the TOP2 antibody. We thank Dr. Ichiro Nakano (University of Alabama, Birmingham, AL), Dr. Charles David James (Northwestern University, Chicago, IL), and Dr. Shi-Yuan Cheng (Northwestern University, Chicago, IL), for the kind gift of the GBM xenografts.
ASJC Scopus subject areas
- General Medicine