title: Hypoxia-inducible factors regulate pluripotency factor expression by ZNF217- and ALKBH5-mediated modulation of RNA methylation in breast cancer cells.
abstract: Exposure of breast cancer cells to hypoxia increases the percentage of breast cancer stem cells (BCSCs), which are required for tumor initiation and metastasis, and this response is dependent on the activity of hypoxia-inducible factors (HIFs). We previously reported that exposure of breast cancer cells to hypoxia induces the ALKBH5-mediated demethylation of N6-methyladenosine (m6A) in NANOG mRNA leading to increased expression of NANOG, which is a pluripotency factor that promotes BCSC specification. Here we report that exposure of breast cancer cells to hypoxia also induces ZNF217-dependent inhibition of m6A methylation of mRNAs encoding NANOG and KLF4, which is another pluripotency factor that mediates BCSC specification. Although hypoxia induced the BCSC phenotype in all breast-cancer cell lines analyzed, it did so through variable induction of pluripotency factors and ALKBH5 or ZNF217. However, in every breast cancer line, the hypoxic induction of pluripotency factor and ALKBH5 or ZNF217 expression was HIF-dependent. Immunohistochemistry revealed that expression of HIF-1α and ALKBH5 was concordant in all human breast cancer biopsies analyzed. ALKBH5 knockdown in MDA-MB-231 breast cancer cells significantly decreased metastasis from breast to lungs in immunodeficient mice. Thus, HIFs stimulate pluripotency factor expression and BCSC specification by negative regulation of RNA methylation.
authors: Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA.|Department of General Surgery, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.
authors: Chuanzhao
authors: C
authors: Zhang
authors: Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors: Wanqing Iris
authors: WI
authors: Zhi
authors: Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA.|McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors: Haiquan
authors: H
authors: Lu
authors: Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA.|McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors: Debangshu
authors: D
authors: Samanta
authors: Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA.|McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors: Ivan
authors: I
authors: Chen
authors: Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.|Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors: Edward
authors: E
authors: Gabrielson
authors: Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA.|Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.|Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA.|Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.|Department of Radiation Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.|Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA.|McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors: Gregg L
authors: GL
authors: Semenza
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives / Q000378:metabolism; D000071502:AlkB Homolog 5, RNA Demethylase / Q000378:metabolism*; D000818:Animals; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D015687:Cell Hypoxia; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D000860:Hypoxia; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors / Q000235:genetics / Q000378:metabolism; D061986:MCF-7 Cells; D008745:Methylation; D051379:Mice; D016513:Mice, SCID; D000071317:Nanog Homeobox Protein / Q000235:genetics / Q000378:metabolism; D014411:Neoplastic Stem Cells / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics*; D034741:RNA, Small Interfering / Q000235:genetics; D015534:Trans-Activators / Q000378:metabolism*; D023041:Xenograft Model Antitumor Assays
chemical_list: D051795:Hypoxia-Inducible Factor 1, alpha Subunit; C000715467:KLF4 protein, human; C000715468:Klf4 protein, mouse; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors; D000071317:Nanog Homeobox Protein; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D015534:Trans-Activators; C113698:ZNF217 protein, human; C010223:N-methyladenosine; C559920:ALKBH5 protein, human; D000071502:AlkB Homolog 5, RNA Demethylase; D000241:Adenosine
keywords: N6-methyladenosine; breast cancer stem cells; hypoxia; metastasis; pluripotency factors