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Reduced expression of the Rassf1a gene and its aberrant DNA methylation in pancreatic duct adenocarcinomas induced by N‐nitrosobis(2‐oxopropyl)amine in hamsters
Author(s) -
Shimizu Kyoko,
Itsuzaki Yumi,
Fujii Hiromasa,
Honoki Kanya,
Tsujiuchi Toshifumi
Publication year - 2008
Publication title -
molecular carcinogenesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.254
H-Index - 97
eISSN - 1098-2744
pISSN - 0899-1987
DOI - 10.1002/mc.20250
Subject(s) - biology , ethionine , methylation , bisulfite sequencing , dna methylation , microbiology and biotechnology , reverse transcription polymerase chain reaction , gene expression , single strand conformation polymorphism , gene , real time polymerase chain reaction , polymerase chain reaction , pancreas , methionine , cancer research , endocrinology , biochemistry , amino acid
Alterations of the Rassf1a gene were investigated in pancreatic duct adenocarcinomas (PDAs) induced by N‐nitrosobis(2‐oxopropyl)amine (BOP) in hamsters. Female Syrian golden hamsters received 70 mg/kg BOP, followed by repeated exposures to an augmentation pressure regimen consisting of a choline‐deficient diet combined with a sequential course of DL ‐ethionine, L ‐methionine, and 20 mg/kg BOP. A total of 15 PDAs were obtained, and total RNAs were assessed by real‐time quantitative reverse transcription (RT)‐polymerase chain reaction (PCR). Expression of the Rassf1a was significantly reduced in PDAs ( P < 0.005) compared with normal pancreatic tissues. For analysis of methylation status, bisulfite sequencing was performed. Normal tissues were all unmethylated in the 5′ upstream region of Rassf1a. In contrast, four PDAs were highly methylated, correlating with reduced expression of the Rassf1a gene. Using reverse transcription (RT)‐polymerase chain reaction (PCR)‐single strand conformation polymorphism (SSCP) analysis, mutations were detected in 3 out of 15 PDAs (20%). These results suggested that alterations of the Rassf1a gene may be involved in development of PDAs induced by BOP in hamsters. © 2007 Wiley‐Liss, Inc.