title: Stable oncogenic silencing in vivo by programmable and targeted de novo DNA methylation in breast cancer.
abstract: With the recent comprehensive mapping of cancer genomes, there is now a need for functional approaches to edit the aberrant epigenetic state of key cancer drivers to reprogram the epi-pathology of the disease. In this study we utilized a programmable DNA-binding methyltransferase to induce targeted incorporation of DNA methylation (DNAme) in the SOX2 oncogene in breast cancer through a six zinc finger (ZF) protein linked to DNA methyltransferase 3A (ZF-DNMT3A). We demonstrated long-lasting oncogenic repression, which was maintained even after suppression of ZF-DNMT3A expression in tumor cells. The de novo DNAme was faithfully propagated and maintained through cell generations even after the suppression of the expression of the chimeric methyltransferase in the tumor cells. Xenograft studies in NUDE mice demonstrated stable SOX2 repression and long-term breast tumor growth inhibition, which lasted for >100 days post implantation of the tumor cells in mice. This was accompanied with a faithful maintenance of DNAme in the breast cancer implants. In contrast, downregulation of SOX2 by ZF domains engineered with the Krueppel-associated box repressor domain resulted in a transient and reversible suppression of oncogenic gene expression. Our results indicated that targeted de novo DNAme of the SOX2 oncogenic promoter was sufficient to induce long-lasting epigenetic silencing, which was not only maintained during cell division but also significantly delayed the tumorigenic phenotype of cancer cells in vivo, even in the absence of treatment. Here, we outline a genome-based targeting approach to long-lasting tumor growth inhibition with potential applicability to many other oncogenic drivers that are currently refractory to drug design.
authors: Cancer Epigenetics Group, The Harry Perkins Institute of Medical Research, Western Australia & School of Anatomy, Physiology and Human Biology, M309, The University of Western Australia, Nedlands, Western Australia, Australia.|Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
authors: S
authors: S
authors: Stolzenburg
authors: Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
authors: A S
authors: AS
authors: Beltran
authors: Lineberger Comprehensive Cancer Center/School of Nursing, University of North Carolina, Chapel Hill, NC, USA.
authors: T
authors: T
authors: Swift-Scanlan
authors: Department of Pathology and Laboratory Medicine, University of North Carolina School of Medicine, Chapel Hill, NC, USA.
authors: A G
authors: AG
authors: Rivenbark
authors: Cancer Epigenetics Group, The Harry Perkins Institute of Medical Research, Western Australia & School of Anatomy, Physiology and Human Biology, M309, The University of Western Australia, Nedlands, Western Australia, Australia.
authors: R
authors: R
authors: Rashwan
authors: Cancer Epigenetics Group, The Harry Perkins Institute of Medical Research, Western Australia & School of Anatomy, Physiology and Human Biology, M309, The University of Western Australia, Nedlands, Western Australia, Australia.|Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
authors: P
authors: P
authors: Blancafort
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism; D002455:Cell Division / Q000235:genetics; D045744:Cell Line, Tumor; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000378:metabolism; D019175:DNA Methylation / Q000235:genetics*; D000090205:DNA Methyltransferase 3A; D015536:Down-Regulation / Q000235:genetics; D044127:Epigenesis, Genetic / Q000235:genetics; D005260:Female; D015870:Gene Expression / Q000235:genetics; D020868:Gene Silencing / Q000502:physiology*; D006801:Humans; D061986:MCF-7 Cells; D051379:Mice; D008819:Mice, Nude; D011401:Promoter Regions, Genetic / Q000235:genetics; D055748:SOXB1 Transcription Factors / Q000235:genetics
chemical_list: C000717967:DNMT3A protein, human; C000715535:Dnmt3a protein, mouse; C527782:SOX2 protein, human; D055748:SOXB1 Transcription Factors; D004248:DNA (Cytosine-5-)-Methyltransferases; D000090205:DNA Methyltransferase 3A