title: Down-regulation of connexin 32 gene expression through DNA methylation in a human renal cell carcinoma cell.
abstract: BACKGROUND
  We have recently reported that connexin (Cx) 32 is down-regulated in a human renal cell carcinoma (RCC) cell (Caki-2 cell).
  
  
  OBJECTIVE
  We postulated that the down-regulation of Cx32 gene in the RCC cell is due to hypermethylation of its promoter region.
  
  
  METHODS
  We estimated methylation status in the promoter region of Cx32 gene in the RCC cell by DNA digestion with methylation-sensitive restriction enzyme and PCR, and methylation-specific PCR (MSP). We also checked the recovery of Cx32 gene expression in the RCC cell treated with a DNA methyltranferase inhibitor, 5-Aza-2'-deoxycytidine (5-Aza-CdR).
  
  
  RESULTS
  Treatment with 5-Aza-CdR resulted in induction of Cx32 expression in the RCC cell. Hypermethylation of the Cx32 promoter region in the RCC cell was confirmed by DNA digestion with methylation-sensitive restriction enzyme and PCR, and MSP.
  
  
  CONCLUSIONS
  We suggest that hypermethylation in the promoter region is a mechanism for the Cx32 gene repression in the RCC cell.
authors.affiliation: Department of Veterinary Pharmacology, College of Bioresource Sciences, Nihon University, Kanagawa, Japan.
authors.forename: Ayako
authors.initials: A
authors.lastname: Hirai
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Yano
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Nishikawa
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Suzuki
authors.forename: Ryuji
authors.initials: R
authors.lastname: Asano
authors.forename: Haruna
authors.initials: H
authors.lastname: Satoh
authors.forename: Kiyokazu
authors.initials: K
authors.lastname: Hagiwara
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yamasaki
mesh_terms: D000704:Analysis of Variance; D001374:Azacitidine / Q000494:pharmacology; D002292:Carcinoma, Renal Cell / Q000235:genetics*; D002450:Cell Communication; D017630:Connexins / Q000235:genetics*; D019175:DNA Methylation; D015536:Down-Regulation; D015870:Gene Expression; D006801:Humans; D015151:Immunoblotting; D007680:Kidney Neoplasms / Q000235:genetics*; D011401:Promoter Regions, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured; D000097002:Gap Junction beta-1 Protein
chemical_list: D001374:Azacitidine; D017630:Connexins; D000097002:Gap Junction beta-1 Protein