title: Silencing NKD2 by Promoter Region Hypermethylation Promotes Esophageal Cancer Progression by Activating Wnt Signaling.
abstract: Naked cuticle homolog 2 (NKD2) was found to be frequently methylated in human breast and gastric cancers. However, the epigenetic changes and mechanisms of NKD2 in human esophageal cancer remain unclear.
  
  
  
  Nine esophageal cancer cell lines and 154 cases of primary esophageal cancer samples were analyzed using methylation-specific polymerase chain reaction, immunohistochemical analysis, Western blot, and xenograft mouse models.
  
  
  
  Loss of NKD2 expression and complete methylation were found in KYSE150 and TE1 cells. Reduced NKD2 expression and partial methylation of the promoter region were observed in KYSE30, KYSE70, KYSE410, KYSE140, and COLO680 cells. High levels of NKD2 expression and unmethylation were detected in KYSE450 and TE8 cells. Reexpression of NKD2 was induced by 5-aza-2'-deoxycytidine in cells in which NKD2 was not expressed or cells in which NKD2 expression was reduced. NKD2 was methylated in 53.2% of human primary esophageal cancer samples (82 of 154), and promoter region hypermethylation was significantly associated with reduced expression of NKD2 (p < 0.01). NKD2 methylation was associated with tumor, node, and metastasis stage and lymph node metastasis (p < 0.01). Our results suggest that NKD2 is regulated by promoter region methylation and that methylation of NKD2 may serve as a prognostic marker in esophageal cancer. Our further studies demonstrate that NKD2 suppresses cell proliferation, colony formation, cell invasion, and migration and also induces G1/S checkpoint arrest in esophageal cancer cells. NKD2 suppressed xenograft tumor growth and inhibited Wnt signaling in human esophageal cancer cells.
  
  
  
  NKD2 is frequently methylated in human esophageal cancer, and the expression of NKD2 is regulated by promoter region methylation. NKD2 suppresses esophageal cancer progression by inhibiting Wnt signaling both in vitro and in vivo.
authors.affiliation: Department of Gastroenterology and Hepatology, Chinese People's Liberation Army General Hospital, Beijing, People's Republic of China.
authors.forename: Baoping
authors.initials: B
authors.lastname: Cao
authors.affiliation: Department of Gastroenterology and Hepatology, Chinese People's Liberation Army General Hospital, Beijing, People's Republic of China; Medical College of NanKai University, Tianjin, People's Republic of China.
authors.forename: Weili
authors.initials: W
authors.lastname: Yang
authors.affiliation: Department of Gastroenterology and Hepatology, Chinese People's Liberation Army General Hospital, Beijing, People's Republic of China.
authors.forename: Yongshuai
authors.initials: Y
authors.lastname: Jin
authors.affiliation: Department of Gastroenterology and Hepatology, Chinese People's Liberation Army General Hospital, Beijing, People's Republic of China; Medical College of NanKai University, Tianjin, People's Republic of China.
authors.forename: Meiying
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Department of Gastroenterology and Hepatology, Chinese People's Liberation Army General Hospital, Beijing, People's Republic of China.
authors.forename: Tao
authors.initials: T
authors.lastname: He
authors.affiliation: State Key Laboratory of Molecular Oncology, Cancer Institute and Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China.
authors.forename: Qimin
authors.initials: Q
authors.lastname: Zhan
authors.affiliation: The Hillman Cancer Center, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania.
authors.forename: James G
authors.initials: JG
authors.lastname: Herman
authors.affiliation: Department of Internal Medicine, Chinese People's Liberation Army General Hospital, Beijing, People's Republic of China.
authors.forename: Guanglin
authors.initials: G
authors.lastname: Zhong
authors.affiliation: Department of Gastroenterology and Hepatology, Chinese People's Liberation Army General Hospital, Beijing, People's Republic of China. Electronic address: mzguo@hotmail.com.
authors.forename: Mingzhou
authors.initials: M
authors.lastname: Guo
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D002135:Calcium-Binding Proteins; D002352:Carrier Proteins / Q000235:genetics*; D045744:Cell Line, Tumor; D019175:DNA Methylation; D018450:Disease Progression; D004938:Esophageal Neoplasms / Q000235:genetics* / Q000473:pathology; D005260:Female; D020868:Gene Silencing; D064593:Heterografts; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D008875:Middle Aged; D011401:Promoter Regions, Genetic; D060449:Wnt Signaling Pathway
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002135:Calcium-Binding Proteins; D002352:Carrier Proteins; C449092:NKD2 protein, human
keywords: DNA methylation; Esophageal cancer; NKD2; Wnt signaling