title: O-LinkedN-Acetylglucosamine (O-GlcNAc) Expression Levels Epigenetically Regulate Colon Cancer Tumorigenesis by Affecting the Cancer Stem Cell Compartment via Modulating Expression of Transcriptional FactorMYBL1.
abstract: To study the regulation of colorectal adenocarcinoma progression byO-GlcNAc, we have focused on theO-GlcNAc-mediated epigenetic regulation of human colon cancer stem cells (CCSC). Xenograft tumors from colon tumor cells withO-linkedN-acetylglucosamine transferase (OGT) knockdown grew significantly slower than those formed from control cells, indicating a reduced proliferation of tumor cells due to inhibition of OGT expression. Significant reduction of the CCSC population was observed in the tumor cells after OGT knockdown, whereas tumor cells treated with theO-GlcNAcase inhibitor showed an increased CCSC population, indicating thatO-GlcNAc levels regulated the CCSC compartment. When grown in suspension, tumor cells with OGT knockdown showed a reduced ability to form tumorspheres, indicating a reduced self-renewal of CCSC due to reduced levels ofO-GlcNAc. ChIP-sequencing experiments using an anti-O-GlcNAc antibody revealed significant chromatin enrichment ofO-GlcNAc-modified proteins at the promoter of the transcription factorMYBL1, which was also characterized by the presence of H3K27me3. RNA-sequencing analysis showed an increased expression ofMYBL1in tumor cells with OGT knockdown. Forced overexpression of MYBL1 led to a reduced population of CCSC and tumor growthin vivo, similar to the effects of OGT silencing. Moreover, two CpG islands near the transcription start site ofMYBL1were identified, andO-GlcNAc levels regulated their methylation status. These results strongly argue thatO-GlcNAc epigenetically regulatesMYBL1, functioning similarly to H3K27me3. The aberrant CCSC compartment observed after modulatingO-GlcNAc levels is therefore likely to result, at least in part, from the epigenetic regulation ofMYBL1expression byO-GlcNAc, thereby significantly affecting tumor progression.
authors.affiliation: From the Department of Biochemistry and Molecular Biology, Complex Carbohydrate Research Center, and.
authors.forename: Huabei
authors.initials: H
authors.lastname: Guo
authors.affiliation: the Boston Children's Hospital, Harvard University, Boston, Massachusetts 02115, and.
authors.forename: Bing
authors.initials: B
authors.lastname: Zhang
authors.affiliation: From the Department of Biochemistry and Molecular Biology, Complex Carbohydrate Research Center, and.
authors.forename: Alison V
authors.initials: AV
authors.lastname: Nairn
authors.affiliation: Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, Georgia 30602.
authors.forename: Tamas
authors.initials: T
authors.lastname: Nagy
authors.affiliation: From the Department of Biochemistry and Molecular Biology, Complex Carbohydrate Research Center, and.
authors.forename: Kelley W
authors.initials: KW
authors.lastname: Moremen
authors.affiliation: the South Carolina College of Pharmacy, University of South Carolina, Columbia, South Carolina 29208.
authors.forename: Phillip
authors.initials: P
authors.lastname: Buckhaults
authors.affiliation: From the Department of Biochemistry and Molecular Biology, Complex Carbohydrate Research Center, and hawkeye@uga.edu.
authors.forename: Michael
authors.initials: M
authors.lastname: Pierce
mesh_terms: D000117:Acetylglucosamine / Q000378:metabolism*; D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D002471:Cell Transformation, Neoplastic / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D003110:Colonic Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D044127:Epigenesis, Genetic / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D014411:Neoplastic Stem Cells / Q000378:metabolism / Q000473:pathology*; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D015534:Trans-Activators / Q000235:genetics*; D014407:Tumor Cells, Cultured; D023041:Xenograft Model Antitumor Assays
chemical_list: C088831:MYBL1 protein, human; D011518:Proto-Oncogene Proteins; D015534:Trans-Activators; D000117:Acetylglucosamine
keywords: O-linked N-acetylglucosamine (O-GlcNAc); colon cancer; epigenetics; gene knockout; glycosylation; glycosyltransferase; stem cells