title: MBD1 is an Epigenetic Regulator of KEAP1 in Pancreatic Cancer.
abstract: BACKGROUND
  MBD1 (Methyl-CpG Binding Domain Protein 1) is highly expressed in pancreatic cancer. Nrf2 (NF-E2 p45-related factor 2) and the 'antioxidant response element' (ARE)-driven genes that NRF2 controls are frequently upregulated in pancreatic cancer and correlate with poor survival. Keap1 (Kelch-like ECH-associated protein 1) is a dominant negative regulator of NRF2 and is reported to be epigenetically regulated by promoter methylation. However, the role of MBD1 with antioxidant response and its association with KEAP1 has never been reported before and remains unclear.
  
  
  OBJECTIVE
  We investigated the role of MBD1 in antioxidant response and its regulatory function in KEAP1 transcription in pancreatic cancer cells.
  
  
  METHODS
  MBD1 was silenced to examine its role in antioxidant response. To explore the underlying mechanism, transcriptional and protein levels of KEAP1 was examined. The correlation between MBD1 and KEAP1 was confirmed in pancreatic cancer tissue samples by using immunohistochemistry (IHC). Dualluciferase reporter assay and Chromatin immunoprecipitation (ChIP) were used to elucidate he mechanism of MBD1 in KEAP1 transcriptional control. Moreover, co-immunoprecipitation (CoIP) assay was performed to uncover the regulatory role of MBD1 in KEAP1 transcription through its association with c-myc.
  
  
  RESULTS
  MBD1 silencing decreased antioxidant response and the related ARE target genes through epigenetic regulation of KEAP1. MBD1 negatively correlated with KEAP1 in pancreatic cancer tissue samples. Moreover, c-myc was a MBD1 interaction partner in KEAP1 epigenetic regulation.
  
  
  CONCLUSIONS
  MBD1 can induce antioxidant response in pancreatic cancer through down-regulation of KEAP1. c-myc plays a key role in MBD1 mediated epigenetic silencing of KEAP1.
authors.forename: B
authors.initials: B
authors.lastname: Zhang
authors.forename: J
authors.initials: J
authors.lastname: Xu
authors.forename: C
authors.initials: C
authors.lastname: Li
authors.forename: S
authors.initials: S
authors.lastname: Shi
authors.forename: S
authors.initials: S
authors.lastname: Ji
authors.forename: W
authors.initials: W
authors.lastname: Xu
authors.forename: J
authors.initials: J
authors.lastname: Liu
authors.forename: K
authors.initials: K
authors.lastname: Jin
authors.forename: D
authors.initials: D
authors.lastname: Liang
authors.forename: C
authors.initials: C
authors.lastname: Liang
authors.forename: L
authors.initials: L
authors.lastname: Liu
authors.forename: C
authors.initials: C
authors.lastname: Liu
authors.affiliation: Department of Oncology, Shanghai Medical College, Fudan University; Pancreatic Cancer Institute, Fudan University, 270 DongAn Road, Shanghai 200032, China. qinyi@fudanpci.org.
authors.forename: Y
authors.initials: Y
authors.lastname: Qin
authors.affiliation: Department of Pancreatic and Hepatobiliary Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University; Pancreatic Cancer Institute, Fudan University, 270 DongAn Road, Shanghai 200032, China. yuxianjun88@hotmail.com.
authors.forename: X
authors.initials: X
authors.lastname: Yu
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D045744:Cell Line, Tumor; D018899:CpG Islands / Q000235:genetics; D004268:DNA-Binding Proteins / Q000378:metabolism*; D044127:Epigenesis, Genetic; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D006801:Humans; D047468:Immunoprecipitation; D000072019:Kelch-Like ECH-Associated Protein 1 / Q000235:genetics* / Q000378:metabolism; D051267:NF-E2-Related Factor 2 / Q000378:metabolism; D010190:Pancreatic Neoplasms / Q000235:genetics*; D011485:Protein Binding; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*; D014162:Transfection
chemical_list: D000975:Antioxidants; D004268:DNA-Binding Proteins; C431364:KEAP1 protein, human; D000072019:Kelch-Like ECH-Associated Protein 1; C066141:MBD1 protein, human; D051267:NF-E2-Related Factor 2; D016271:Proto-Oncogene Proteins c-myc; D034741:RNA, Small Interfering; D014157:Transcription Factors