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Huisman C, van der Wijst MGP, Schokker M, Blancafort P, Terpstra MM, Kok K, van der Zee AGJ, Schuuring E, Wisman GBA, Rots MG. Re-expression of Selected Epigenetically Silenced Candidate Tumor Suppressor Genes in Cervical Cancer by TET2-directed Demethylation. Mol Ther 2015; 24:536-47. [PMID: 26686387 DOI: 10.1038/mt.2015.226] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 12/11/2015] [Indexed: 12/18/2022] Open
Abstract
DNA hypermethylation is extensively explored as therapeutic target for gene expression modulation in cancer. Here, we re-activated hypermethylated candidate tumor suppressor genes (TSGs) (C13ORF18, CCNA1, TFPI2, and Maspin) by TET2-induced demethylation in cervical cancer cell lines. To redirect TET2 to hypermethylated TSGs, we engineered zinc finger proteins (ZFPs), which were first fused to the transcriptional activator VP64 to validate effective gene re-expression and confirm TSG function. ChIP-Seq not only revealed enriched binding of ZFPs to their intended sequence, but also considerable off-target binding, especially at promoter regions. Nevertheless, results obtained by targeted re-expression using ZFP-VP64 constructs were in line with cDNA overexpression; both revealed strong growth inhibition for C13ORF18 and TFPI2, but not for CCNA1 and Maspin. To explore effectivity of locus-targeted demethylation, ZFP-TET2 fusions were constructed which efficiently demethylated genes with subsequent gene re-activation. Moreover, targeting TET2 to TFPI2 and C13ORF18, but not CCNA1, significantly decreased cell growth, viability, and colony formation in cervical cancer cells compared to a catalytically inactive mutant of TET2. These data underline that effective re-activation of hypermethylated genes can be achieved through targeted DNA demethylation by TET2, which can assist in realizing sustained re-expression of genes of interest.
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Affiliation(s)
- Christian Huisman
- Department of Pathology and Medical Biology, University Medical Center Groningen (UMCG), University of Groningen, Groningen, The Netherlands.,Current address: Department of Pediatrics, Oregon Health and Science University, Portland, Oregon, USA
| | - Monique G P van der Wijst
- Department of Pathology and Medical Biology, University Medical Center Groningen (UMCG), University of Groningen, Groningen, The Netherlands
| | - Matthijs Schokker
- Department of Pathology and Medical Biology, University Medical Center Groningen (UMCG), University of Groningen, Groningen, The Netherlands
| | - Pilar Blancafort
- Cancer Epigenetics Group, The Harry Perkins Institute for Medical Research, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Martijn M Terpstra
- Department of Genetics, University Medical Center Groningen (UMCG), University of Groningen, Groningen, The Netherlands
| | - Klaas Kok
- Department of Genetics, University Medical Center Groningen (UMCG), University of Groningen, Groningen, The Netherlands
| | - Ate G J van der Zee
- Department of Gynecological Oncology, University Medical Center Groningen (UMCG), University of Groningen, Groningen, The Netherlands
| | - Ed Schuuring
- Department of Pathology and Medical Biology, University Medical Center Groningen (UMCG), University of Groningen, Groningen, The Netherlands
| | - G Bea A Wisman
- Department of Gynecological Oncology, University Medical Center Groningen (UMCG), University of Groningen, Groningen, The Netherlands
| | - Marianne G Rots
- Department of Pathology and Medical Biology, University Medical Center Groningen (UMCG), University of Groningen, Groningen, The Netherlands
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