title: DNMT1-microRNA126 epigenetic circuit contributes to esophageal squamous cell carcinoma growth via ADAM9-EGFR-AKT signaling.
abstract: OBJECTIVE
  MicroRNAs (miRNA) are involved in and are controlled by epigenetic regulation, and thereby form a reciprocal regulatory circuit. Using next-generation sequencing (NGS)-based miRNA profiling, this study aimed to discover esophageal squamous cell carcinoma (ESCC)-specific miRNAs and miRNA-related epigenetic modulations.
  
  
  METHODS
  NGS-based miRNA profiles were generated for four pairs of ESCC tissues and adjacent normal tissues. In situ hybridization was used to assess miRNA expression and its correlation with prognosis. miRNA-related DNA methylations were identified using bisulfite genomic sequencing, and the role of DNA methyltransferase 1 (DNMT1) was investigated using RNA interference. miRNA targets were screened by mRNA sequencing, and functional validation was performed in vitro and in vivo.
  
  
  RESULTS
  NGS-based miRNA profiling identified 78 differentially expressed miRNAs in ESCC. Among them, microRNA126-3p (miR-126) was significantly downregulated, and its downregulation correlated with poor ESCC prognosis. Downregulation of miR-126 was due to promoter hypermethylation of its host gene, Egfl7. DNMT1 was aberrantly upregulated in ESCC and responsible for the hypermethylation of Egfl7. Intriguingly, DNMT1 was suppressed by overexpression of miR-126, indicating the existence of a regulatory feedback circuit. ADAM9 was identified as a key target of miR-126. Ectopic expression of miR-126 or silencing of ADAM9 reduced ESCC cell proliferation and migration by inhibiting epidermal growth factor receptor-AKT signaling.
  
  
  CONCLUSIONS
  Our results indicate that miR-126 is a potential prognostic indicator for ESCC and suggest that a novel "DNMT1-miR-126 epigenetic circuit" is involved in ESCC progression. Consequently, miR-126-based epigenetic modulations may provide a basic rationale for new approaches to antitumor therapeutics.
authors.affiliation: Department of Immunology and Key Laboratory of Medical Molecular Virology of MOE/MOH, School of Basic Medical Sciences, Fudan University, Shanghai, China. Biotherapy Research Center, Fudan University, Shanghai, China.
authors.forename: Ronghua
authors.initials: R
authors.lastname: Liu
authors.affiliation: Department of Thoracic Surgery, Zhongshan Hospital, Fudan University, Shanghai, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Gu
authors.affiliation: Department of Immunology and Key Laboratory of Medical Molecular Virology of MOE/MOH, School of Basic Medical Sciences, Fudan University, Shanghai, China. Biotherapy Research Center, Fudan University, Shanghai, China.
authors.forename: Pei
authors.initials: P
authors.lastname: Jiang
authors.affiliation: Department of Immunology and Key Laboratory of Medical Molecular Virology of MOE/MOH, School of Basic Medical Sciences, Fudan University, Shanghai, China. Biotherapy Research Center, Fudan University, Shanghai, China.
authors.forename: Yijie
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: Department of Immunology and Key Laboratory of Medical Molecular Virology of MOE/MOH, School of Basic Medical Sciences, Fudan University, Shanghai, China. Biotherapy Research Center, Fudan University, Shanghai, China.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Immunology and Key Laboratory of Medical Molecular Virology of MOE/MOH, School of Basic Medical Sciences, Fudan University, Shanghai, China. Biotherapy Research Center, Fudan University, Shanghai, China.
authors.forename: Xuechao
authors.initials: X
authors.lastname: Jiang
authors.affiliation: Department of Immunology and Key Laboratory of Medical Molecular Virology of MOE/MOH, School of Basic Medical Sciences, Fudan University, Shanghai, China. Biotherapy Research Center, Fudan University, Shanghai, China.
authors.forename: Enyu
authors.initials: E
authors.lastname: Huang
authors.affiliation: Department of Immunology and Key Laboratory of Medical Molecular Virology of MOE/MOH, School of Basic Medical Sciences, Fudan University, Shanghai, China. Department of Hematology/Oncology, The Second Hospital of Anhui Medical University, Hefei, Anhui Province, China.
authors.forename: Shudao
authors.initials: S
authors.lastname: Xiong
authors.affiliation: Department of Thoracic Surgery, Zhongshan Hospital, Fudan University, Shanghai, China.
authors.forename: Fengkai
authors.initials: F
authors.lastname: Xu
authors.affiliation: Department of Immunology and Key Laboratory of Medical Molecular Virology of MOE/MOH, School of Basic Medical Sciences, Fudan University, Shanghai, China. Biotherapy Research Center, Fudan University, Shanghai, China.
authors.forename: Guangwei
authors.initials: G
authors.lastname: Liu
authors.affiliation: Department of Thoracic Surgery, Zhongshan Hospital, Fudan University, Shanghai, China. yiwei_chu@126.com gedi6902@hotmail.com.
authors.forename: Di
authors.initials: D
authors.lastname: Ge
authors.affiliation: Department of Immunology and Key Laboratory of Medical Molecular Virology of MOE/MOH, School of Basic Medical Sciences, Fudan University, Shanghai, China. Biotherapy Research Center, Fudan University, Shanghai, China. yiwei_chu@126.com gedi6902@hotmail.com.
authors.forename: Yiwei
authors.initials: Y
authors.lastname: Chu
mesh_terms: D051722:ADAM Proteins / Q000378:metabolism; D002294:Carcinoma, Squamous Cell / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000378:metabolism*; D019175:DNA Methylation; D044127:Epigenesis, Genetic; D066246:ErbB Receptors / Q000378:metabolism; D004938:Esophageal Neoplasms / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D000077277:Esophageal Squamous Cell Carcinoma; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics*; D016147:Genes, Tumor Suppressor; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D017403:In Situ Hybridization; D053208:Kaplan-Meier Estimate; D008565:Membrane Proteins / Q000378:metabolism; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D046888:Tissue Array Analysis
chemical_list: C527111:MIRN126 microRNA, human; D008565:Membrane Proteins; D035683:MicroRNAs; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; C000619380:DNMT1 protein, human; C512478:EGFR protein, human; D066246:ErbB Receptors; D051057:Proto-Oncogene Proteins c-akt; D051722:ADAM Proteins; C098339:ADAM9 protein, human